HALOGEN-CATALYZED PYRIDINE N-OXIDE OXIDATION OF ISONITRILES TO ISOCYANATES
HALOGEN-CATALYZED PYRIDINE N-OXIDE OXIDATION OF ISONITRILES TO ISOCYANATES
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DOI：
10.1021/jo01281a052
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发表时间：
1967-01-01
影响因子：
3.6
通讯作者：
KRUTZSCH, H
中科院分区：
文献类型：
--
作者：
JOHNSON, HW;KRUTZSCH, H
本文研究了异丙基异腈与N-氧化吡啶在氯、溴、碘存在下的反应。与碘反应生成异丙基异氰酸酯;发现反应的动力学为整体三级。与溴反应产生初始加合物（II），其结构已经确定。II与异腈进一步反应得到异丙基异氰酸酯。氯与异丙基异腈和吡啶N-氧化物的反应在非常缓慢的反应中得到异氰酸酯。苯基和对甲氧基异腈也与吡啶N-氧化物和碘反应生成异氰酸酯，测定了反应动力学，并与异丙基异氰酸酯的反应动力学进行了比较。最近报道了异丙基和苯基异腈在卤素存在下与二甲基亚砜氧化生成相应的异氰酸酯。1以前曾报道过用氧化汞2和臭氧3将异腈氧化成异氰酸酯，以及异腈二卤化物与水反应（可能通过异氰酸酯生成胺）4。本文报道了异腈氧化机理的研究结果。对于动力学研究来说，异丙基异腈碘-二甲基亚砜反应的反应温度过高。初步研究表明，吡啶N-氧化物、碘和异丙基异腈在氯仿中也产生异丙基异氰酸酯。异丙基-，苯基-和p-茴香腈与吡啶N-氧化物和碘在氯仿溶剂中的反应动力学，使用红外光谱法测定，以跟踪在2250 cm-1处的产物峰强度的增加。反应似乎是干净的三级（一级在异腈，吡啶N-氧化物，和碘）。碘没有被消耗，并且实验上观察到伪二级动力学。反应在正常密封池中进行，使用仪器的恒温器（32±0.5）进行温度控制。速率常数的10%的一致性似乎令人满意的建立反应的顺序。每次运行都是精确的伪二阶图形。非消费-
The reactions of isopropylisonitrile with pyridineN-oxide in the presence of chlorine, bromine, and iodine have been studied. Reaction with iodine yields isopropyl isocyanate; the kinetics of the reaction were found to be over-all third order. Reaction with bromine yields an initial adduct (II) whose structure has been determined. Further reaction of II with isonitrile yielded isopropyl isocyanate. Reaction of chlorine with isopropylisonitrile and pyridine N-oxide gave the isocyanate in a very slow reaction. Phenyl-and p-anisylisonitriles also gave isocyanates with pyridineN-oxide and iodine; the kinetics were measured and compared with those of iso-propyl isocyanate.Recently the oxidations of isopropyl-and phenyl-isonitriles to the corresponding isocyanates with dimethyl sulfoxide in the presence of halogen were re-ported. 1 Previously the oxidation of isonitriles to isocyanates with mercuric oxide2 and ozone3 and the reaction of isonitrile dihalides with water (which yields the amine, presumably via the isocyanate) 4 havebeen reported. In this paper are reported the results of studies on the mechanism of isonitrile oxidation. Reaction temperatures for the isopropylisonitrileiodine-dimethyl sulfoxide reaction were undesirably high for kinetic studies. Preliminary studies showed that pyridine N-oxide, iodine, and isopropylisonitrile also yielded isopropyl isocyanate in chloroform. The kinetics of the reaction of isopropyl-, phenyl-, and p-anisylisonitriles with pyridine N-oxide and iodine in chloroform solvent were determined using infrared spectroscopy to follow the increase in intensity of the product peakat 2250 cm-1. The reactions appeared to be cleanly third order (first order in isonitrile, pyri-dine N-oxide, and iodine). Iodine was not consumed, and pseudo-second-order kinetics were observed experi-mentally. The reaction was run in a normal sealed cell using the thermostating of the instrument (32±0.5) for temperature control. The10% agreement of the rate constants appeared satisfactory to establish the order of the reaction. Each run was accurately pseudo second order graphically. The nonconsump-