Methods i) and ii) need a-keto-amides prepared, e.g., from a-ketoacids [85JCS(P1)769]

or a-keto-acyl chlorides. [90CC1321] The only previous direct conversion of a-

hydroxycarboxylic acids to a-hydroxyamides is their reaction with N-sulfinylamines

(RNSO). [86TL1921]

 After reaction of BtSO2CH3 with 2-hydroxy-2-phenylacetic acid (4.6) in the

presence of triethyl amine, we failed to isolate the corresponding a-hydroxy-N-

acylbenzotriazoles probably due to their instability. However, when one equiv. of aniline

or 4-methylaniline was added into the mixture obtained by refluxing 4.6, BtSO2CH3 and

Et3N in dry THF for about 20 min, a-hydroxyamides 4.7a and 4.7b were obtained in

68% and 72% yields, respectively (Scheme 4-2). Products 4.7a and 4.7b were not formed

in the absence of BtSO2CH3. When n-butylamine or pyrrolidine was used as the amine

reactant, no desired products were obtained. The role of BtSO2CH3 is the same as with

other reactions.

 i) BtSO2CH3
 OH OH
 C-COOH Et3N/ C-CONHR
 H ii) RNH2 H

 DL-4.6 4.7a, R = C6H5
 4.7b, R = 4-CH3C6H4

Scheme 4-2. Reaction of BtSO2CH3 with 2-hydroxy-2-phenylacetic acid

4.2.6 Preparation of 1-(1H- 1,2,3-Benzotriazol- -yl)-2,2,3,3,4,4,4-heptafluorobutan- 1-one
(4.8) and its Perfluoroacylation with Primary and Secondary Amines.

 In 1997, we reported (trifluoroacetyl)benzotriazole as a convenient

trifluoroacetylating agent for amines and alcohols. [97JOC726] (Trifluoroacetyl)-

benzotriazole was prepared by the reaction of benzotriazole with trifluoroacetic

anhydride [(CF3CO)20] and, thus, trifluoroacetic acid was formed as a byproduct. The