2.3- Dibromopropanoic acid

The Gabriel-Cromwell reaction of amines with chiral c/., 3-unsaturated a-bromo carbonyl compounds was exploited for the synthesis of aziridine-2-carboxylic acid derivatives. 79 This procedure was optimized for a solid support synthesis in which the peptide resin was acylated with 2,3-dibromopropanoic acid active ester in the presence of 3 equivalents of NMM to produce directly on resin the a-bromoacrylamide for the addition of amines to produce the aziridine ring. 80 ... 

The high regiospecifity observed in the formation of 1, 4.-benzoxazines (356) from o-aminophenols (354) and esters of 2,3-dibromopropanoic acid (355) in the presence of base is explained by the initial elimination of hydrogen bromide from the ester, followed by Michael addition of the aminophenol and finally ring-... 

Dibromopropanoic acid (C H 02Br2) values in Vol.3, p.333) Tribromoacetic acid (C2H02Br3)... 

The reactivity of bromine trifluoride is significantly enhanced by Lewis acids, such as tin(IV) chloride, antimony(V) chloride, titanium(IV) chloride, which are exchanged to the corresponding fluorides and give complexes with bromine trifluoride. Thus, the reaction of 2,2,2-tri-fluoroethyl or 2,2,3,3-tetrafluoropropyl 2,3-dibromopropanoate with bromine trifluoride in the presence of 1 mol% tin(IV) chloride affords the corresponding 2,3-difluoropropanoates in 85-87% yield.110... 

An alternative route starting from serine 73 or threonine 68 74 makes use of diethoxy-triphenylphosphorane. Attempts to asymmetrically synthesize (25)-aziridine-2-carboxylic acid (1) by treating a, 3-dibromopropanoates with chiral amines 75 or by the Staudinger reaction from oxirane-2-carboxylic acid ester 70,76 leads to optically impure products, whereas 3-alkyl derivatives of tert-butyl aziridine-2-carboxylates can be prepared with high cis-selectivity from a-halo ester enolates and jV-trimethylsilyl imines. 77 Moreover, when optically... 

C4H5CI02 trans-2-chloro 2-butenoic acid 22038-56-8 485.15 42.459 1.2 2785 C4H6Br202 methyl 2,3-dibromopropanoate 1729-67-5 479.15 41.884 1,2... 

From in situ generated N -(3,3-dibromoacryloyl)hydrazinecarboxylic acid ethyl ester. The previously unreported 5-bromopyrazol-3-one 274 was prepared on a multigram scale by adaptation of standard literature procedures (04SL795) (Scheme 60). Thus, l,l,3,3-tetrabromopropan-2-one 268 underwent a Favorski rearrangement to 3,3-dibromopropanoic... 

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