Bwiti (PVC-Analog Taste-Tester)
04-01-02 00:40
No 290505
      Piperonyl Chloride From Hypochlorite?     

From: ../rhodium/chemistry /benzylchloride.html

Ca(OCl)2 Chlorination of Toluene
Toluene and dry Calcium Hypochlorite (bleaching powder) are heated together to 105C in the abscence of other reagents. This avoids by-product formation. If equal amtounts are used, volume-wise, there is a high conversion.

  I went to the patent that describes the procedure above, but only toluene was mentioned. I want to know if 1,3-benzodioxole can be used instead to obtain piperonyl chloride? Has anyone here tried this? If this works, then how the hell can the 1,3-benzodioxole/piperonyl chloride be separated from eachother when the reaction is finished, without a vacuum pump? Can the chloride be crashed out with some type of solvent? Peace!cool

  ChemGrrl is in a beautiful place, and she hears our prayers.
(Chief Bee)
04-01-02 01:24
No 290526
      Ca(OCl)2 chlorination     

You cannot start with 1,3-benzodioxole, I believe, you must use 3,4-methylenedioxytoluene. Direct chlorination of the ring would be too unspecific, that's why bromination is preferred for functionalization of aromatics.
(PVC-Analog Taste-Tester)
04-01-02 04:57
No 290638

  3,4-methylenedioxytoluene? What would I need to methylenate to obtain this? Thanks!

  ChemGrrl is in a beautiful place, and she hears our prayers.
(Chief Bee)
04-01-02 19:10
No 290957

3,4-dihydroxytoluene aka 4-methylcatechol. I'd say that even 3,4-metylenedioxytoluene is not heavily watched, and it is also mentioned extensively in the patent literature.
(PVC-Analog Taste-Tester)
04-01-02 23:42
No 291082
      Cool, thanks! I went to http://gb.espacenet.     

  Cool, thanks! I went to and looked-up 3,4-methylenedioxytoluene, but I got zero results. I'll try to find a synonym for this compound, then look it up again. If I wanted to make this compound, would I just do the same I'd do to make 3,4-methylenedioxybenzene, except replace the plain-old catechol with 4-methylcatechol? Here's what I plan on dreaming: Methylenate 4-methylcatechol to 3,4-methylenedioxytoluene, reflux this with a hypochlorite to produce piperonyl chloride, then convert this to piperonal with hexamine and 50% acetic acid or 60% aqueous ethanol[Total Synthesis 2, pg.241], 70% yield.
  Here's what I need to know: After the piperonyl chloride is filtered off from the hypochlorite, how can the unreacted 3,4-methylenedioxytoluene(MDT) be removed? Can I distill off the MDT under normal pressure on an oil bath without destroying the piperonyl chloride? Peace!cool

Love my country, fear my government.
(Chief Bee)
04-02-02 00:05
No 291098

USP 4335263 or 3979415 perhaps?
(PVC-Analog Taste-Tester)
04-02-02 11:26
No 291400
      I looked-up one of the refs that were sited in ...     

  I looked-up one of the refs that were sited in one of the patents you mentioned, and I found methylenedioxybenzene chloromethylation that doesn't require HCl gas, just a saturated aqueous solution.

Process For The Preparation
Of Heliotropin

Example IV
Preparation of heliotropin from methylene
dioxybenzene(MDOB) by chloromethylation
and reaction with potassium 2
propane-nitronate in aqueous t
(a) To hydrochloric acid (1 litre, saturated at 0 ) was added paraformaldehyde (52.5 g); when this had been dissolved by stirring a further quantity (52.5 g) of paraformaldehyde was added, followed by MDOB (535 g). The mixture was stirred vigorously and kept at 19--200C by occasional cooling. After 65 minutes the mixture was allowed to settle and the heavy organic layer was washed once with water (250 ml). The separated acid and water washings were extracted twice with carbon tetrachloride (50 ml) to yield on evaporation a further 11 g of oil which was added to the main product.


Love my country, fear my government.
(Chief Bee)
04-02-02 12:15
No 291409

Note that is says "Saturated at 0C", which corresponds to 825 g/l - not the usual 37%.

The interesting thing about what you found is the conversion of a benzyl chloride to an aldehyde using the potassium salt of 2-nitropropane.
(Hive Bee)
04-03-02 01:59
No 291612

(PVC-Analog Taste-Tester)
04-03-02 03:14
No 291646
      "hass-bender" What? Is that sexually explicit ...     


  What? Is that sexually explicit slang? Look pal, just because your girlfriend's out of town, doesn't mean I'll sleep with you.laugh Check your email, and tell me if you got all three of those attachments I scanned from T.S.2.

"Note that is says "Saturated at 0C", which corresponds to 825 g/l - not the usual 37%."

  My water raft is a solution to yet another problem. I could fill it with HCl, attach it to a cold flask of 37% hydrochloric, then place a ten pound weight on the raft. 

Love my country, fear my government.
(Hive Bee)
04-03-02 03:40
No 291653

Bwiti, you're just absolutely adorable.  and although it does sound... explicit after thinking about it.  No, it's just a named reaction.  look it up- it's pretty interesting.  aurelius thinks that Rhodium or somebody (Lugh, maybe?) that it was a disproportionation reaction. 
(PVC-Analog Taste-Tester)
04-03-02 05:42
No 291700
      Did a search on altavista/google and got a ...     

  Did a search on altavista/google and got a general idea of what the hass-bender reaction is; pretty cool!cool

Love my country, fear my government.
(Chief Bee)
04-03-02 21:23
No 291900
(Master Whacker)
04-03-02 21:51
No 291911

Hey Rhody,

We must give credit where its due:  remember Lugh originally found the ref for converting secondary halides to ketones in high yield using the KOH/2-Nitropropane system?smile  Same process applies to benzylic halides as Bwiti pointed.

Lughs finding has been very fruitful to me so I thought I'd speak up.
(Chief Bee)
04-03-02 22:09
No 291924

I know - I didn't know how secret he wanted that to be. Does the method work on aliphatic chlorides? PM me about your results with that method.
04-04-02 13:44
No 292292
      Halides to Carbonyls
(Rated as: excellent)

The following is from JACS 77, 1114 (1954), it describes a synthesis of MDP2P in 90% yield from bromosafrole.



A reaction between 2-nitropropane and benzylidene-bis-dimethylamine gave acetoxime and N.N-dimethylbenzamide-Benzylidene-bis-piperidine and 2-nitropropane gave acetoxime and benzoylpiperidine. The reactions appear to proceed by formation of aminobenzyl 2-propanenitronates which disproportionate into acetoxime and benzamides, thus establishing a relationship with the reaction of halides with sodium 2-propanenitronate to form esters with subsequent disproportionation. The latter reaction has been found to go well in wet solvents and even in water. The reaction has been extended to synthesize the aliphatic aldehydes, undecanal and dodecanal, as well as 3,4-METHYLENEDIOXYPHENYLACETONE and cyclohexadione.

Among a number of routes that could conceivably lead to a phenyl substituted -butylamine was a Mannich reaction involving benzaldehyde, dimethylamine and 2-nitropropane. When this reaction was attempted, no Mannich base formed. The products of the reaction were acetoxime and N,N-dimethylbenzamide. The same products, plus dimethylamine, resulted from an attempted abbreviated Mannich reaction1 with preformed benzylidene-bis-dimethylamine and 2-nitropropane. The expected reaction, forming Mannich base, should have been carbon alkylation of the active hydrogen compound, 2-nitropropane, by the cation (1) resulting from the interaction of benzaldehyde and dimethylamine.

The unexpected formation of acetoxime and dimethylbenzamide is explicable only if the two result from the disproportionation of the ester, alpha-dimethylaminobenzyl 2-propanenitronate, arising from oxygen alkylation of 2-propanenitronic acid by the cation. Although this reaction has not been reported previously, it may be classified among a number of reported reactions (2) of halides and salts of nitronic acids giving rise to carbonyl compounds corresponding to the halides and oximes corresponding to the nitronic acids. Earlier examples of similar reactions involve mononitroparaffins other than 2-nitropropane. There can be little doubt that these reactions proceed through the disproportionation of an intermediate nitronic ester into an oxime and a carbonyl compound. The major side-reaction appears to be carbon-alkylation when alkylating with highly activated halogen compounds.

A reaction converting an aldehyde to an amide, while a fascinating facet, seems of limited interest. The same reaction was used to convert benzylidene-bis-piperidine to benzoylpiperidine, but failed with an aliphatic aldehyde, n-hexaldehyde. Heating n-hexaldehyde, dimethylamine and 2-nitropropane led to a partial recovery of starting materials and a 61% yield of the Knoevenagel product, 2-hexylidenehexaldehyde. The formation of the latter product rather than the nitronic ester (and disproportionation products) was probably favored by both the temperature and basicity. The possibility of the Knoevenagel reaction, when catalyzed by secondary amines, proceeding via the bis-amine has been mentioned previously. (1) A similar reaction using the preformed bis-dimethylamine from 3,5,5-trimethylhexaldehyde was contemplated, but it was abandoned when only the metholamine, N-(1-hydroxy-3,5,5-trimethylhexyl)-dimethylamine, was obtained from the attempted preparation of bis-dimethylamine.

The two successful examples of amide preparation seem to be dependent on temperature, requiring some forcing. On refluxing benzaldehyde, aqueous dimethylamine and 2-nitropropane in ethanol for two hours, the yield of N,N-dimethylbenzamide was 37%. Benzylidene-bis-dimethylamine and 2-nitropropane without solvent at 120-130, produced a 94% yield. That the difference is due to temperature and not to the use of preformed bis-amine was shown clearly by the benzoylpiperidine synthesis. Heating benzylidene-bis-piperidine and 2-nitropropane in refluxing ethanol for four hours led to no benzoylpiperidine, 93% of the benzylidene-bis-piperidine being recovered. On dispensing with solvent and heating at 130-140, benzoylpiperidine was obtained in 54% yield.
The preparation of dimethylbenzamide in aqueous alcohol suggested that the more general reaction, converting halides to carbonyl compounds, might not necessarily require metallic sodium and anhydrous alcohol, and might be a preparative reaction for aliphatic carbonyl compounds under milder conditions. The formation and disproportionation of 2-propanenitronic esters have been found to take place smoothly and with good yields for monocarbonyl compounds. It is not necessary to use metallic sodium and anhydrous alcohol. The reactions go well in 95% ethanol using salts formed in the solvent from 2-nitropropane and sodium or potassium hydroxide before adding the halide. By this procedure 3,4-methylenedioxyphenylacetone, undecanal and dodecanal were obtained in good yield. It has been reported (2) that aliphatic aldehydes are not obtained under anhydrous conditions,
To test the feasibility of using water without alcohol, a suspension of benzyl chloride was heated and stirred in an aqueous solution of potassium 2-propanenitronate, giving a 49% yield of benzaldehyde. The possibility that the aqueous conditions might operate against a carbon-alkylation side-reaction had to be discarded when para-nitrobenzyl chloride was treated with an aqueous solution of sodium 2-propanenitronate and found to give a 59% yield of the carbon-alkylation product, 2-methyl 2-nitro-l-(para-nitrophenyl) -propane, and no para-nitrobenzaldehyde.

The presence of acetoxime in water-insoluble aldehydes or ketones presents no problem since it is readily removable from ether solution by water. In some preliminary experiments, last traces of acetoxime appeared as crystals in the condenser from which it was sublimed into the trap by using warm water in the condenser. Acetoxime presents a more serious problem when the other product is also water soluble, e.g., succindialdehyde and 1,2-cyclohexadione. Preparation and separation of a derivative was considered inadvisable because of the amounts involved, and distillation of the mixtures was attempted. Distillation was only moderately successful for cyclohexadione, because decomposition during the prolonged heating held the yield down to 30%. In the attempted preparation of succindialdehyde from 1,4-dichloro-butane, decomposition during distillation was more rapid, and no product could be obtained from the residual tar after removal of the acetoxime fraction. This latter case and other polyfunctional possibilities require a more searching investigation.
Both chloro and bromo compounds have been converted successfully to carbonyl compounds, usually at reflux temperatures. Activated halogen as in 2-chlorocyclohexanone reacts vigorously, and it is advisable to add the reagent slowly with cooling. Final refluxing is necessary, both for completion of the metathesis and disproportionation of the nitronic ester.

Experimental (5)


Benzaldehyde (106 g., 1 mole) was poured into a 1-liter flask containing 400 g. of 25% aqueous dimethylamine. The mixture was swirled occasionally during 10 minutes warming on the steam-cone. After cooling, the aqueous layer was saturated with potassium carbonate and the upper layer separated with the aid of 100 ml. of benzene. The benzene layer was dried over potassium carbonate, the benzene removed under reduced pressure and the residue distilled. The product was collected at 57-60 (0.9 mm.), 143 g. (80%). Anal.    Calcd. for C11H18N2: N, 15.7.   Found: N, 15.6.


Benzylidene-bis-dimethylamine (44.5 g., 0.25 mole) was heated in a 200-ml. flask, fitted with a dropping funnel and reflux condenser with drying tube, in an oil-bath at 120-130. 2-Nitropropane (22.2 g., 0.25 mole) was added dropwise in the course of 2.5 hours with continuous evolution of dimethylamine. Heating was continued one additional hour and then the light amber reaction mixture was distilled. The forerun was collected at 35-70 (20 mm.) and the dimethylbenzamide at 94-96 (0.5 mm.), 35 g. (94%).

The forerun was redistilled, giving white crystals in the receiver and condenser, at 55 (20 mm.). On recrystallization from heptane, it melted at 62-63, no depression of m.p. on mixing with an authentic sample of acetoxime.

Redistillation of the dimethylbenzamide gave b.p. 266, m.p. 38. Because the material was water insoluble and the m.p. low, it was analyzed. Anal.    Calcd. for C9H11NO:  N, 9.39.   Found:  N, 9.40.

A portion was hydrolyzed with 20% sulfuric acid, precipitating benzoic acid, m.p. and mixed m.p. 121-122, after recrystallization from water. The hydrolysis filtrate was made alkaline and distilled, trapping the dimethylamine distillate in ice-water. Addition of phenyl isothiocyanate to the distillate precipitated N,N-dimethyl-N'-phenylthiourea, m.p. 133-135 after recrystallization from ethanol.

Another preparation of N,N-dimethylbenzamide was made by mixing 0.25 mole each of benzaldehyde (26.5 g.), 2-nitropropane (22.2 g.) and 25% aqueous dimethylamine (45 g.), with 50 ml. of ethanol. The reaction was heated under reflux for two hours, cooled, and extracted with benzene (three 50-ml. portions). The solvents were removed under reduced pressure and the residue distilled, obtaining 12.5 g. of benzaldehyde at 40-45 (0.8 mm.), phenylhydrazone m.p. 158, (7) and 14.0 g. (37%) of N,N-dimethylbenzamide at 100-104 (0.8 mm.).


2-Nitropropane (17.8 g., 0.2 mole) and 25.8 g. (0.1 mole) of benzylidene-bis-piperidine (8) were mixed in a 100-mI. flask fitted with a reflux condenser. The flask was heated in an oil-bath at 130-140 for three hours. After cooling, the dark oil was poured into 200 ml. of 2.5 N hydrochloric acid and shaken vigorously. The dark heavy layer was taken up in ether, washed with water to remove acetoxime, dried over magnesium sulfate and distilled. After removal of ether and 2-nitropropane, there was obtained 2 g. of benzaldehyde at 46 (0.8 mm.) and 10.2 g. (54%) of benzoylpiperidine at 136-139 (0.8 mm.) as a pale lemon oil which solidified to a white solid, m.p. 46-48, no depression of m.p. on mixing with an authentic sample.


This compound was the product of an unsuccessful attempt to prepare N,N-dimethylcaproamide carried out in the following manner, n-Hexaldehyde (50 g., 0.5 mole) was added to 110 g. of 25% aqueous dimethylamine (1.1 moles) and heated for five minutes on the steam-cone. The mixture was cooled, saturated with potassium carbonate, and the upper phase transferred to a 500-ml. flask fitted with a dropping funnel and a reflux condenser. It was heated on the steam-cone while 44.5 g. (0.5 mole) of 2-nitropropane was added drop-wise in the course of two hours, and heating continued for one more hour. After cooling, the mixture was taken up in 50 ml. of ether and washed with 100 ml. of N hydrochloric acid and three 50-ml. portions of water. After drying over magnesium sulfate, ether, unreacted alpha-hexaldehyde and 2-nitropropane were removed at 30 mm. The 2-hexylidene-hexaldehyde, 28 g. (61%), distilled at 80-82 (0.8 mm.). It was redistilled at 79 (0.7 mm.), with virtually no change in constants, n>D 1.4566, dt 0.8438, MD 58.80 (calcd. 59.06). The 2,4-dinitrophenylhydrazone melted at 132-133 (from ethanol). Anal. Calcd. for C18.H26N4O4: N, 15.5. Found: N, 15.5.


Aqueous dimethylamine (200 g. of 25%, 1.1 moles) in a 500-ml. flask was cooled in an ice-bath and 71 g. (0.5 mole) of 3,5,5-trimethylhexaldehyde was added slowly with stirring. After complete addition, the reaction was heated on a steam-bath for 15 minutes, cooled, saturated with potassium carbonate, and the upper layer separated with the aid of ether. The ether layer was dried over potassium carbonate and distilled, yielding 60 g. (64%) of the methylolamine at 81 (22 mm.).
Anal. Calcd. for C11H25NO: neut. equiv., 187. Found: neut. equiv., 187.
On treating with picric acid in ethanol, dimethylamine picrate formed, m.p. 159-160. The methylolamine, treated with 2,4-dinitrophenylhydrazine and hydrochloric acid in ethanol, gave a 2,4-dinitrophenylhydrazone, m.p. 92-93, no depression of m.p. when mixed with a sample prepared from 3,5,5-trimethylhexaldehyde.


In a 200-ml. two-necked flask fitted with a mechanical stirrer and a reflux condenser, 14 g. (0.25 mole) of potassium hydroxide was dissolved in 25 ml. of water. 2-Nitropropane (22.2 g., 0.25 mole) was added, and the hot mixture stirred to a clear yellow solution. Benzyl chloride (31.7 g., 0.25 mole) was added, and the mixture stirred and heated under reflux for two hours. After cooling, the mixture was filtered through a glass wool plug to remove precipitated potassium bromide, washing with 50 ml. of ether. The ether layer was separated, washed with 25 ml. of water, dried over magnesium sulfate, and distilled. A small amount of acetoxime crystallized in the condenser (b.p. 52 (18 mm.)), m.p. and mixed m.p. 61-62. The benzaldehyde was collected at 62 (1 mm.), 13 g. (49%); phenylhydrazone, m.p. 157-158.(7)

2-Methyl-2-nitro-1 -(para-nitrophenyl)-propane

Sodium hydroxide (12 g., 0.3 mole) was dissolved in 100 ml. of water and 26.7 g. (0.3 mole) of 2-nitropropane added and stirred to complete solution. To the solution was added 51.5 g. (0.3 mole) of para-nitrobenzyl chloride. The suspension was stirred and heated under reflux for 2.5 hours. After cooling, the supernatant water was decanted, the heavy oil taken up in 100 ml. of ether, washed twice with water, and the ether evaporated. The residual oil was crystallized from 100 ml. of hot ethanol, yielding 37.5 g. (56%) of crude product, m.p. 58-62. Recrystallization from ethanol raised the m.p. to 64-65, no depression on mixing with an authentic specimen. (9)
Undecanal- A solution of 2.80 g. of potassium hydroxide and 4.55 g. of 2-nitropropane in 75 ml. of 95% ethanol was added dropwise in the course of 45 minutes to a refluxing solution of 11.75 g. of undecyl bromide (all reactants 0.05 M) in 50 ml. of 95% ethanol. Refluxing was continued for an additional 15 minutes. The solution was cooled and decanted from a deposit of sodium bromide; ethanol was removed in vacua, the residue taken up in 75 ml. of ether, washed with water (2 X 30 ml.) and dried over magnesium sulfate. After removal of ether, undecanal (10a) was distilled at 64-66 (0.7 mm.), yield 7.3 g. (85%), n25 1.4500; 2,4-dinitrophenylhydrazone, m.p. 105-106; oxime, m.p. 71-72.

A second preparation was started at room temperature and then heated under reflux for two hours, resulting in a similar yield.

This latter experiment illustrates a general procedure for monocarbonyl compounds. In the same manner there was prepared: dodecanal, b.p. 126-138 (15 mm.), (10b) 46% yield from dodecyl bromide; semicarbazone, m.p. 100-101 (10c) 2,4-dinitrophenylhydrazone, m.p. 102-103; 3,4-METHYLENEDIOXYPHENYLACETONE, B.P. 110-111 (0.8 MM.), (10D) 90% YIELD FROM 1-PIPERONYL-L-BROMOETHANE (11); SEMICARBAZONE, M.P. 158-159 (10D); 1,2-cyclohexadione, b.p. 80-81 (16 mm.),(11) 30% yield from 2-chlorocyclohexanone (13) (reaction begun in ice-bath); bis-phenylhydrazone, m.p. 150-151.(10f)

(1) S. V. Lieberman and B. C. Wagner, J. Org. Chem., 14, 1001 (1949).
(2) H. B. Haas and M. L. Bender, THIS JOURNAL, 71, 1767, 3482 (1949); Org. Syntheses, 30, 99 (1950).
(3) L. Weisler and R. W. Helmkamp, THIS JOURNAL, 6T, 1167 (1945).
(4) A small sample of dry potassium 2-propanenitronate, which had been stored in a stoppered flask several weeks, exploded violently immediately after opening the flask preliminary to weighing a portion. Consequently the use of dry salts is considered extremely hazardous. Solutions of sodium or potassium 2-propanenitronate are safe to handle. An attempt to burn a molar alcohol solution of the sodium salt produced no untoward results: the alcohol burned evenly, only the last few milliliters evidenced some sparking and spattering. apparently because of condensations under the basic reaction conditions. Under the "aqueous" conditions, the reactions are approximately pH 8.5 initially and pH 7 finally. For very sensitive aldehydes, a solution of sodium 2-propanenitronate could be added to the halide, keeping the pH constantly near neutrality.
(5) Microanalyses by Dr. Wilhelm Reiss and staff,
(6) N.N-Dimethylbenzamide is water insoluble. It was originally reported (10e) as very soluble in water and the error is repeated in various handbooks.
(7) R. L. Shriner and R. C. Fuson, "Identification of Organic Compounds." 2nd Ed., John Wiley and Sons, Inc., New York, N. Y., 1940. (S) E. Staple and E. C. Wagner, J. Org. Chem.. 14, 559 (1949).
(8) E. Staple and E. C. Wagner J Org  Chem , 14, 559 (1949)
(9) H. B. Hass, E. J. Berry and M. L. Bender, THIS JOURNAL, 7l, 2290 (1949).
(10) Beilstein, "Handbuch der Organischen Chemie," 4th ed., Julius Springer, Berlin; (a) 1, 712; (b) 1, 714; (c) 2nd suppl., 1, 769; (d) 19, 131; (e) 9, 201; (f) 1st suppl.. 7, 310.
(11) S. V. Lieberman, G. P. Mueller and E. T. Stiller, THIS JOURNAL, 69, 1540 (1947).
(12) L. W. Butz. B. L. Davis and A. M. Gaddis, J. Org. Chem., 12, 122 (1947).
(13) P. D. Bartlett and R. H. Rosenwald, THIS JOURNAL, 56, 1990 (1934).

This reaction can also produce aldehydes. Another application of this reaction would be the conversion of 1-phenyl-2-chloropropane into phenylacetone. If isopropyl alcohol can be converted into 2-nitropropane or the gas phase nitrator is perfected, this would become a good route for all of the bees. It is also very likely that chlorosafrole can be disproportionated to MDP-2-P as bromosafrole.
(Hive Bee)
06-26-04 23:59
No 515613
      More halides to carbonyls
(Rated as: good read)

The following is related article which fits nicely in this thread, even though:

''This is an old thread to which posting is discouraged.''

As the article deals with 'activated' halides, it may not fare as well as the 2-nitropropane method for the oxidation of 1-phenyl-2-halopropanes to phenylacetones. However, the yields are higher for the oxidation of benzyl halides to benzaldehydes. The piperonyl chloride Bwiti originally enquired about would of course give piperonal upon oxidation:

Sur L'Utilisation de L'Ion Chromate Comme Agent Oxydant Dans La Synthese De Composes Carbonyles A Partir De Derives Halogenes Actives
Vu Moc Thuey et Pierre Maitte
Bulletin des Societes Chimiques Belges
, 98(3), 1989

The reaction between activated alkyl halides and K2CrO4 in DMF or DMSO provides a convenient synthetic route to corresponding carbonyl compounds.