Stable and easily accessible N-acylbenzotriazoles, derived from a variety of aliphatic, unsaturated, (hetero)aromatic, and N-protected alpha-amino carboxylic acids, were reacted with Grignard and heteroaryllithium reagents to afford corresponding ketones in good to excellent yields.

Easily accessible 1,1'-sulfonylbis(benzotriazole) (Bt2SO2, 1) reacts with secondary amines at room temperature to afford (i) the corresponding o-sulfamidotriazobenzenes 2a-d (53-75%) via concurrent substitution of the first and ring opening of the second benzotriazolyl group and (ii) N-sulfonylbenzotriazoles 3b,c,e,f (7-73%). 1-(Morpholine-4-sulfonyl)-1H-benzotriazole 3c reacts with piperidine, pyrolidine, and N-methylpiperazine under microwave irradiation (120 W) at 120 degrees C for 10 min to give the unsymmetrical sulfamides 4a-c (80-90%).

Diverse hydroxyarenecarboxylic acids afford stable N-(hydroxyaroyl)benzotriazoles that react with heteroaryl, alkyl, and aryl Grignard or lithium reagents to give the corresponding hydroxyaryl ketones in 51-94% yields.Hydroxyaryl ketones 1 are precursors for the synthesis of biologically active chalcones, 2 flavones, 2b,3 isoflavones, 4 and xanthones. 5 Aryl o-hydroxyaryl ketones exhibit protein kinase B inhibitor, 6 cyclin-dependent kinase inhibitor, 7 and cysteine protease modulator activities. 8 Aryl hydroxyaryl ketone moieties occur in natural products such as cotoin, 9 balanol, 10 and daunorubicin. 11 Many aryl hydroxyaryl ketones including dioxybenzone, 12 mexenone, 13 oxybenzone, 14 benzophenone-6, 15 and benzoresorcinol 16 are used as ultraviolet screens.The conventional Friedel-Crafts acylation of phenols and naphthols with acid chlorides in the presence of Lewis acid catalysts 5,17 and Fries-type rearrangement of suitable aryl esters, 18 which are both frequently used for the preparation of hydroxyaryl ketones, are often unselective in that ortho-and para-acylation of phenols and naphthols result leading to mixture of products. Moreover, acid chlorides are sensitive to moisture and hence they are difficult to handle. 19 Alternative, less frequently used, syntheses of hydroxyaryl ketones include (i) palladiumcatalyzed coupling of o-hydroxyaryl aldehydes with hypervalent iodonium salts 20 and (ii) intramolecular acyl radical [1,6]-ipso-substitution reactions. 21 N-Acylbenzotriazoles are easily prepared activated derivatives of carboxylic acids. 22 Applications of N-acylbenzotriazoles include: (i) N-acylation of amines, 23 amides, 23,24 and sulfonamides, 25 (ii) O-acylation of aldehydes, 26 steroids, 27 hydroxyterpenes and alcohols, 28 (iii) many C-acylations of, for example, pyrroles and indoles, 29 ketones and heteroaromatics, 30 alkyl sulfones, 31 alkyl cyanides, 32 alkyl azines, 33 a-nitroalkanes, 34 furan and thiophene; 35 syntheses of (iv) peptides, 36 (v) oxazolines, 37 (vi) esters, 38 (vii) benzodioxin-4-ones, 39 (viii) ketones, 40 (ix) benzodiazepin-2-ones, 41 (x) thiol esters, 42 (xi) alcohols, 43 (xii) acyl azides and hydrazides, 44 (xiii) heteroaromatics, 45 and (xiv) heterocycles. 46

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