Arulsamy Navamoney, Bohle D Scott
Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071-3838, USA.
J Org Chem. 2006 Jan 20;71(2):572-81. doi: 10.1021/jo051998p.
[reaction: see text] Reactions of nitric oxide with enolates derived from aliphatic methyl ketones containing alpha-methylene or alpha-methine groups and with enolates derived from alpha,alpha'-dimethylene or alpha,alpha'-dimethine ketones yield mono- or bis(diazeniumdiolate) products. Diazeniumdiolation occurs in the following order: alpha-methine > alpha-methylene > alpha-methyl. The amount of the base used alters the extent of diazeniumdiolation and the course of the reaction. Mono- and bis(diazeniumdiolate)-substituted methyl ketones are cleaved in the presence of excess base before and after the subsequent diazeniumdiolation of the alpha-methyl group. Similar to the trihalogenated methyl groups in the base-assisted halogenation reactions of methyl ketones, the bis(diazeniumdiolate)-substituted alpha-methylene and alpha-methyl groups act as leaving groups in the presence of excess base. The reaction of nitric oxide with a (approximately 20:80, cis/trans) mixture of 2,6-cyclohexananone yields the cis and trans isomers of 2,6-dimethylcyclohexanone-2,6-bis(diazeniumdiolate) in 12.9% and 57.6% yield. Single-crystal X-ray diffraction data determined for potassium cis-2,6-dimethylcyclohexanone-2,6-bis(diazeniumdiolate), cis-14b, reveal that the N(2)O(2-) substituent is planar with considerable delocalization of a double bond over the anionic four-atom group. Except for one of the diazeniumdiolate products, namely, potassium propanoate 2,2-bis(diazeniumdiolate), 8b, all are stable in neutral and basic aqueous media. Compound 8b slowly decomposes in neutral aqueous solution releasing nitrous oxide and nitric oxide gases but is stable in basic aqueous media. Differential scanning calorimetry data measured for the diazeniumdiolate products indicate that they decompose exothermally with most of them undergoing explosive decomposition at moderately high temperatures (181-274 degrees C).
[反应：见正文] 一氧化氮与源自含有α-亚甲基或α-次甲基的脂肪族甲基酮的烯醇盐以及与源自α,α'-二亚甲基或α,α'-二亚甲基酮的烯醇盐反应，生成单或双（二氮烯二醇盐）产物。二氮烯二醇化反应按以下顺序发生：α-次甲基＞α-亚甲基＞α-甲基。所用碱的量会改变二氮烯二醇化的程度和反应进程。在α-甲基随后发生二氮烯二醇化反应之前和之后，单和双（二氮烯二醇盐）取代的甲基酮在过量碱存在下会发生裂解。与甲基酮碱辅助卤化反应中的三卤代甲基类似，双（二氮烯二醇盐）取代的α-亚甲基和α-甲基在过量碱存在下可作为离去基团。一氧化氮与2,6-环己酮的（约20:80，顺式/反式）混合物反应，以12.9%和57.6%的产率生成2,6-二甲基环己酮-2,6-双（二氮烯二醇盐）的顺式和反式异构体。对顺式-2,6-二甲基环己酮-2,6-双（二氮烯二醇盐）钾盐（顺式-14b）测定的单晶X射线衍射数据表明，N(2)O(2-)取代基呈平面结构，双键在阴离子四原子基团上有相当程度的离域。除了一种二氮烯二醇盐产物，即丙酸2,2-双（二氮烯二醇盐）钾盐（8b）外，所有产物在中性和碱性水性介质中都很稳定。化合物8b在中性水溶液中缓慢分解，释放出一氧化二氮和一氧化氮气体，但在碱性水性介质中稳定。对二氮烯二醇盐产物测定的差示扫描量热法数据表明，它们会放热分解，大多数在中等高温（181 - 274℃）下发生爆炸分解。
