Reaction with phosphoryl chloride

In the Meisenheimer reaction of quinoline 1-oxides chlorine atoms usually enter the 2-and 4-positions, but not exclusively. 2,4-Dibromoquinoline 1-oxide was 6-chlorinated (57MI1), and the 5- and 6-nitroquinoline 1-oxides were 3-chlorinated to some extent (44JOC302). This reaction with phosphoryl chloride-phosphorus pentachloride has also been used in the preparation of chlorinated phenanthrolines (88YZ1148). 

Several variations of this synthetic route have been developed. For example, condensation of the methyltriazole (21) with thiourea gives the thiol derivative (22), and reaction with phosphoryl chloride in dimethylformamide converts the amino-amide to a cyano-amidine, which can be reduced to the 4-amino-5-aminomethyl derivative (Scheme 47). ... 

Compound 85 was dehydrogenated at 300° over palladium black under reduced pressure to a pyridine derivative 96 which was independently synthesized by the following route. Anisaldehyde (86) was treated with iodine monochloride in acetic acid to give the 3-iodo derivative 87. The Ullmann reaction of 87 in the presence of copper bronze afforded biphenyldialdehyde (88). The Knoevenagel condensation with malonic acid yielded the unsaturated diacid 91. The methyl ester (92) was also prepared alternatively by a condensation of 3-iodoanisaldehyde with malonic acid to give the iodo-cinnamic acid (89), followed by the Ullmann reaction of its methyl ester (90). The cinnamic diester was catalytically hydrogenated and reduced with lithium aluminium hydride to the diol 94. Reaction with phosphoryl chloride afforded an amorphous dichloro derivative (95) which was condensed with 2,6-lutidine in liquid ammonia in the presence of potassium amide to yield pyridine the derivative 96 in 27% yield (53). 

This reaction with phosphoryl chloride in dimethylformamide. 

In addition to the reactions with phosphoryl chloride mentioned above. 

Starting material is readily available from acetoacetanilide via 4-methylcarbostyril and reaction with phosphoryl chloride. ... 

There are a number of very useful processes in which the iV-oxide function allows the introduction of substituents, usually at an a position, and in the process the oxide function is removed reaction with phosphoryl chloride is an example. 

The conversion of the carbonyl group in pyridones into a leaving group has a very important place in the chemistry of pyridones, the most frequently encountered examples involving reaction with phosphoryl chloride and/or phosphorus pentachloride leading to the chloro-pyridine, via an assumed dichlorophosphate... 

Chlorination of a benzo-annulated pyrimido[4,5-c]pyridazin-5-ol is achieved by the reaction with phosphoryl chloride 39 the chlorine atom can be substituted by the methoxy group.39... 

Another method of aromatization is the transformation of 1,2,4-triazinones into chloro-1,2,4-triazines by reaction with phosphoryl chloride, phosphorus pentachloride, or thionyl chloride,158, 160 176 , 79 183-191 as shown for the synthesis of 3-chloro-l,2,4-triazines, 18, 5-chloro-1,2,4-triazines 20, and 6-chloro-l,2,4-triazines 22. 

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