3- chloro-2-hydroxy

Chlorination of 2-hydroxy-4//-pyrido[l,2-n]pyrimidin-4-one with NCS in a mixture of AcOH and TFA at room temperature for 72 h yielded a 3-chloro-2-hydroxy derivative (95JMC4687). Bromination of 2-chloro-4//-pyrido[l, 2-n]pyrimidone with Br2 in a mixture of CH2CI2 and pyridine at room temperature for 15 min gave a 3-bromo derivative (00BMC751). 

Cleavage of a,[i-epoxy ketones.1 The reagent (1), possibly (CH3)2SC1, formed from DMSO and ClSi(CH3)3, cleaves a,(3-epoxy ketones to 2-chloro-3-hydroxy ketones with high regioselectivity (equation I). If the epoxide has a phenyl substituent, 3-chloro-2-hydroxy ketones are formed (equation II). 

The use of nitroxynil (14) and the biphenols (16a,b and 18a,b) along with menichlopholan (23) has also been extended to the treatment of liver fluke infections. Accordingly, disophenol (11), nitroxynil (14), bithionol (18a), bithionol sulfoxide (18b), niclofolan (menichlopholan, 23) and bis(3-chloro-2-hydroxy-5-nitrophenyl)sul-phide (24) have been used to treat F. hepatica and f. gigantica infections in sheep and cattle [23]. 

Methylphenyl 3-chlorobenzoate has been catalytically rearranged in refluxing nitrobenzene solution containing Nafion-H during 12 hours to give 3-chloro-2 -hydroxy-5 -methylbenzophenone in 71% yield (ref. 19). 

Enzymatic Preparation of (I5,2R)-[3-Chloro-2-hydroxy-l-(phenylmethyl) propyl]-carbamic acid, 1,1-Dimethyl-ethyl... 

Atazanavir 11 (Figure 16.4A) is an acyclic aza-peptidomimetic, a potent HIV protease inhibitor [43,44] approved recently by the U.S. Food and Drug Adminstration for treatment of autoimmune diseases (e.g., AIDS). An enzymatic process has been developed for the preparation of (lS,2/ )-[3-chloro-2-hydroxy-l-(phenylmethyl)pro-pyljcarbamic acid, 1,1-dimethylethyl ester 13 (Figure 16.4B), akey chiral intermediate... 

Amino-l-hydroxy-2-(3-chloro-2-hydroxy-5-nitrophenylazo)naphthalene- 74PM 3,6-disulfonic acid (Gallion)... 

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