6914-70-1

Upstream product

• 17639-93-9 2-chloro-propionic acid methyl ester 
• 80-62-6 methacrylic acid methyl ester 
• 61168-38-5 (1R,2S)-1,2-Dimethyl-cyclopropane-1,2-dicarboxylic acid monomethyl ester 
• 2121-68-8 dimethyl 2,4-dimethylpentanedioate 
• 186581-53-3 diazomethane 
• 198344-26-2 (-)-menthyl 2-chloropropanoate 
• 699-49-0 cis-1,2-Dimethyl-1,2-cyclopropanedicarboxylic acid 
• 817-76-5 2-chloropropyl methyl ester 

Downstream Products

• 884-79-7 3-phenyl-1,5-dimethyl-3-azabicyclo-<3.1.0>hexane-2,4-dione 
• 119908-77-9 c-2-Chlorformyl-1,2-dimethyl-r-1-cyclopropancarbonsaeure 
• 6914-67-6 1,2-dimethyl-cyclopropane-1r,2c-dicarboxylic acid anhydride 
• 699-49-0 cis-1,2-Dimethyl-1,2-cyclopropanedicarboxylic acid 

Relevant academic research and scientific papers

Stereoselective 1,3-debromination reactions

The metallate, PPN(1+)Cr(CO)4NO(1-), was used for the 1,3-debrominative reductive cyclization of the (+/-) and meso isomers of dimethyl 2,4-dibromoglutarate and dimethyl 2,4-dibromo-2,4-dimethylglutarate.In both (+/-) isomers, the reaction is stereospecific in giving the trans cyclopropane product.In the meso case, the reaction is unselective in the first case, but distinctly favors the cis cyclopropane isomer in the second set of compounds.This (+/-) and meso pair thus represent the first example of near stereospecifity in the debromination of both 1,3-dibromo diasteromers.Using an enantiomerically enriched dimethyl 2,4-dibromo glutarate, and determining the absolute stereochemistry of the cyclopropane product, it was found that a strict double inversion () mechanism is involved in the (+/-) debromination reaction and presumably also in the near-stereospecific meso case reported above.

Cyclopropanediamines, 3. - Pure Diastereomers of 1,2-Cyclopropanedicarboxylic Acids and Derivatives

Efficient preparations of pure diastereomers of dimethyl 1,2-cyclopropanedicarboxylates 2, dicarboxylic acids 3, dicarbonyl dichlorides 4, and dihydrazides 5 are reported.Mixtures of diastereomers of dimethyl dicarboxylates 2a, b, d, e are obtained from α,β-unsaturated methyl carboxylates 7 and methyl α-chlorocarboxylates 8 as well as from 7c, d and the sulfur ylide 10 (2c, d).The diastereomers are separated by fractionating distillations (2a, b, c, e) or crystallization (2d) on a 100-g to 1-kg scale (d.e. >99percent).Only low yields of 2c are obtained in the reaction of methyl crotonate (7c) with methyl α-chloroacetate (8a), since 7c predominantly dimerizes to afford 12.The diesters 2 are converted into the pure diastereomeric diacids 3, dicarbonyl dichlorides 4, and dihydrazides 5. 3,3-Dimethyl-cis-1,2-cyclopropanedicarboxylic acid (cis-3f) is obtained by trans-->cis isomerization of trans-3f with the help of acetic anhydride and sodium acetate as catalyst.The configurations of 2-6 and 12 are confirmed by 1H NMR spectroscopy.Derivatives of cis-1,2-dimethyl-1,2-cyclopropanedicarboxylic acid tend to form bicyclic products.Thus, the reaction of cis-3e with phosphorus pentachloride yields mainly the cyclic anhydride 6e and only small amounts of the dicarbonyl dichloride cis-4e.Furthermore, the dihydrazide cis-5e slowly cyclizes in the solid state to give the N-aminoimide 13 and hydrazine, a reaction which is fast in solution.Pure 13 is obtained by thermolysis of cis-5e at 60-65 deg C under high vacuum.