[Chemical reaction: See text] Benzotriazole reagents for thioacylation (RCSBt), thiocarbamoylation (RR'NCSBt), aryl/alkoxythioacylation (ROCSBt), and aryl/alkylthiothioacylation (RSCSBt) are synthesized, and their utility is assessed by syntheses of representative heteroaryl thioureas 3a-g, thioamides 15a-s, thionoesters 16a-h, thiocarbamates 17a-e, dithiocarbamates 18a-d, thiocarbonates 19a-c, and dithiocarbonates 20a-c.

ACID WITH IMIDAZOLE REAGENT KEY WORDS: I m i d a z o l e , 7 -a m i n o c e p h a l o s p o r a n i c a c i d , spect rophotometry . A.A. Alwarthan, S. Abdelfattah and N.M. Zahran C h e m i s t r y D e p a r t m e n t , ABSTRACT A s p e c t r o p h o t o m e t r i c method is p r o p o s e d f o r t h e determination of 7-aminocephalosporanic a c i d (7-ACA) . The method is based on t h e formation of acetamidocephalosporanic a c i d which is then d i r e c t l y measured in aqueous solution 249 2 50 ALWARTHAN, ABDELFATTAH, AND ZAHRAN (pH 11.5) a t 316 nm. The m t h o d c h a r a c t e r i z e s a newly developed, s e n s i t i v e procedure for the determination of the drug. The e f f e c t of s e v e r a l reaction c o n d i t i o n s were i n v e s t i g a t e d . Beer's l a w was obeyed over the concentration range 0.08-0.56 @ml. Less than 16 pg/ml of t h e drug (defined as the m u n t of t h e drug that gave a s i g n a l of twice the tackground noise) can be determined. The r e l a t i v e standard d e v i a t i o n was 1.8 ' % f o r 0.25 rrg/ml (for 6 r e p l i c a t e determinations) .