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Additional HC1 was added as required to maintain the solution acidity. After an appropriate time period, usually 1 h, the products were isolated by dilution with water followed by filtration or extraction with ether. Table I presents results for a variety of structural types. As evident, the method appears suitable for conjugated derivatives which are activated by a nitro group (entry 14) or by two -positioned electron-withdrawing substituents including ester, cyano, lactone, ketone, or amide in varying combinations. Singly substituted double bonds as in ethyl cinnamate (entry 16) are resistant and aryl substitution enhances the reduction rate (entry 15). The method is quite selective in that other functional groups are unaffected including amido (entries 7,10,13), aromatic and aliphatic nitro (entries 4-6, 9,14,17) or cyano (entries 8-13) moieties, esters (entries 1-12,15,16), lactones (entries 17-19), or aryl ketones (entries 17-19). Furthermore, in contrast to analogous reductions with NaBHq,51•'® cyano esters are not further reduced to the corresponding cyano alcohols. The use of acid, although not essential, results in higher yields (compare entries 1 and 3), ostensibly by rapid protonation of initially produced stable a carbanions before side reactions can intervene. This is evidenced by the relatively high yield of 1 -methyl-2-phenylnitroethane obtained (entry 14) compared to previous investigations73'15 coupled with the absence of dimeric Michael products which are concomitantly produced with other hydride reagents.73'11 Experimental Section Materials. NaBH3CN was obtained from Aldrich Chemical Co. and used without purification. Starting materials were either obtained commercially or prepared by standard procedures.12 All new compounds gave satisfactory elemental analysis and showed spectral (ir and NMR) data consistent with the structures. Elemental analyses were provided by Chemalytics, Inc., Tempe, Ariz., copies of which have been provided the Editor.General Reduction Procedure. The general procedure utilized is presented in the text and is described below for the reduction of 6-nitro-3-benzoylcoumarin.6-Nitro-3-benzoyl-3,4-dihydrocoumarin. A slurry of 6-nitro-3-benzoylcoumarin (2.95 g, 10 mmol), NaBH3CN (0.69 g, 11 mmol), and a small amount of bromocresol green indicator in 25 ml of ethanol was magnetically stirred while concentrated HC1 was added dropwise until the color changed to yellow. Periodically, additional HC1 was added in order to maintain the yellow color. After 1.5 h the reaction mixture was diluted with ca. 150 ml of water and cooled and the resulting while needles were filtered and dried under vacuum (2.54 g, 86%). The ir and NMR indicated complete reduction of the double bond.

The use of iodine as an oxidizing agent for phenolic compounds has been explored. The reaction has been conducted in methanol containing such alkali as potassium hydroxide and, depending on the nature of the substituents and on the amount of iodine employed, leads to iodination, oxidation to give a stable phenoxy radical, oxidative dimerization, or benzylic oxidation. In general the reaction proceeds smoothly at room temperature, and under appropriate conditions yields of products are good to excellent. Oxidative dimerization of 2,4-and 2,6-di-tert-butylphenols involves iodination followed by iodine-catalyzed dimerization. The oxidation of 4methylphenols with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone in methanol has been carried out for comparison.

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