Isocyanates benzoyl isocyanate

Phosgene reacts exothermically with thiirane in two steps (Scheme 36) (77MI50602). 3,5-Dinitrobenzoyl chloride and benzoyl fluoride initiate polymerization of thiirane. A novel reaction of benzoyl isocyanate or trichloroacetyl isocyanate, which yields ethylenethiol derivatives from epithiochlorohydrin (2-chloromethylthiirane), 2-methylthiirane or cyclohexene episulfide, has been reported (Scheme 37) (71BAU2432). 

A-Carbamoyldiaziridines can open the three-membered ring and recyclize through the carbamoyl nitrogen, as demonstrated in a benzoyl isocyanate adduct (74JOC3198) and in the formation of (140) (79JOC3935). 

A very similar reagent is benzyl t-butyl imidodicarboxy late 27, which is prepared from benzyl alcohol and benzoyl isocyanate, followed by exhaustive acylation with t-butoxycarbonyl chloride. Aminolysis of the resulting triacylamine yields 27. Treatment of the sodium salt of compound 27 with alkyl halides, followed by hydrolysis, gives primary amines53. 

The synthetic route to pyrroloquinoxalines 286 (Scheme 102) starts with /V-phenylpyrrole (284). With isocyanate 284 affords via an aza-Wittig reaction the isolable carbodiimide (285), which is converted in turn by pyrolysis into the final product 286. Treatment of 284 with benzoyl isocyanate gives... 

N-3-Substituted 2-thioxo-4-quinazolinones 859 are formed when alkyl or aryl isothiocyanates are reacted with anthranilic acids or esters 857, <2001JME1710, 2002AP556, 2004JC0584, 2006JME2440>. The intermediate di-substituted thiourea 858 is normally not isolated, but is directly ring-closed in situ to the thioxoquinazolinone product 859. When 3-unsubstituted products are required, benzoyl isocyanate can be used <20008714>. 

The flash vacuum thermolysis of 4-hydroxy-2,5-diphenyl-l,3-oxazin-6-one resulted in carboxy(phenyl)ketene and benzonitrile as the major and benzoyl isocyanate as the minor product. This was interpreted in terms of the influence of the tautomeric forms on the thermal fragmentation pathways <2007JOC1399>. 

As part of a mechanistic and synthetic study of nucleophihc carbenes the spirocyclic 4(5/l)-oxazolone 18 has been obtained from benzoyl isocyanate (Scheme 6.1) Thermal extrusion of nitrogen from the 1,3,4-oxadiazoline 14 produced the carbonyl ylide 15 that fragmented via loss of acetone to the aminooxycarbene 16. Spectroscopic data [gas chromatography-mass spectrometry (GC-MS), infrared (IR), proton and C-13 nuclear magnetic resonance ( H and NMR)] of the crude thermolysate was consistent with 18. The formation of 18 was rationalized to result from nucleophihc addition of 16 to benzoyl isocyanate followed by cyclization of the dipolar intermediate 17. Thermolysis of 19 and 21 under similar reaction conditions afforded 20 and 22 respectively, also identified spectroscopically as the major products in the thermolysate. 

The reaction of Ph 3P=CH2 with benzoyl isocyanate takes place in a 1 2 ratio with loss of benzene to afford the ylide 173 <71JOC2029> and treatment of either Ph3P=CHC02Me or Ph3P=CHC02Et with aryl cyanates, Ar-O-CN, results in formation of the pyrimidine ylides 174 <67CB187>. An alternative means of access to 171 (R = cyclohexyl) is provided by... 

Isocyanate Benzoyl Azide. See 2 Azido-formylphenylisocyanate in Vol 1, p A638-R... 

The second example is more reasonable but 3-phenyl-l,3-oxazetidin-3-one is obtained in low yield from formaldehyde tetramer and phenyl isocyanate (Scheme 92) (67TL3637). Perhalogenated (F or Cl) ketones also add to methylisocyanate catalyzed by CsF, BF3 or in liquid S02 solvent in 5-70% yield (67JOC2960). Dichloroethylene is reported to add to benzoyl isocyanate in 23% yield, also by addition across the carbon-oxygen bond of the isocyanate (70BAU1479). 

The 1,3,5-thiadiazepine (559) has been prepared by the thermal rearrangement of the [4 + 2] cycloadduct (558) of the azirine (557) and thiobenzoyl isocyanate (74JOC3763). The benzoyl isocyanate adduct does not rearrange to give an oxadiazepine. 

Azidofor my I phony I isocyanate (2-Isocyanate Benzoyl Azide), OC N-CONj, mw 188.15, N 29.78% Needles (from benz), mp 60° (dec) on careful heating explodes violently on rapid heating or on impact. It can be prepd by heating phthalic acid diazide in benz... 

Sulfoxides can act as an S—O two-atom fragment in [4 + 2] condensations. Thus reaction of DMSO with benzoyl isocyanate in the presence of boron trifluoride etherate (75IZV1206) gives the 1,3,2,5-dioxathiazine (248). Boron trifluoride induced condensation of DMSO with Ar-benzoyl-S,5-bis(trifluoromethyI)sulfimide (249) gives the 1,3,2,4,5-dioxadithiazine (117) (78JA985), and the iV-acylimine (250) also gives a 1,3,2,5-dioxathiazine (251) on reaction with DMSO (80ZOR463). 

Diazoalkane adds to carbodiimides and ketenimines, preferentially to the carbon-nitrogen double bond of the latter, but the triazoline undergoes spontaneous isomerization to the triazole.367-371 The only exception is the addition of ethyl diazoacetate to benzoyl isocyanate where an isolable... 

H)-Oxazolones were unknown until 1949 when the 2-phenyl derivative was prepared by the action of diazomethane on benzoyl isocyanate (equation 145) (49JA4059). Treatment of the phospholene (293) with acyl isocyanates (294 R = Ph, MeO or Ph2N) affords 5-acetyl-5-methyl-4(5.flr)-oxazolones (equation 146). 

Amino-l,3,4-oxadiazoles form amides with acetic anhydride, benzoyl chloride and arenesulfonyl chlorides. With phenyl isocyanate, 5-substituted 2-amino-l,3,4-oxadiazoles yield urea derivatives (71a). Using an excess of phenyl isocyanate an isocyanate (71b) is produced, and with three equivalents of phenyl isocyanate l,3,4-oxadiazolo[3,2-a]-l,3,5-triazine-5,7-diones are obtained (Chapter 4.29) (74T221). 

Benzoyl isocyanate trimerizes to form 7-benzoylimino-2,5-diphenyloxazolo[5,4-rf]-[l,3]oxazine (243). The latter in the presence of sodium methoxide undergoes a Dimroth-type rearrangement to yield the fused pyrimidine (244) after debenzoylation (72JOC2583). 

Similar to the reaction of the corresponding thiocyanates, attack of benzoyl isocyanates on enaminones occurs at the -position. The intermediate is isolated in benzene at room temperature in one case and then cyclized to the pyridone12 (equation 8). 

Mixtures of azetidinones 11 and dihydrooxazinones 12 are produced from ketone enamine and trichloroacetyl or benzoyl isocyanate via a common zwitterionic intermediate (equation 9)27. 

Dihydro-l,3-oxazin-4-ones 375 are obtained from various enamines 374 and benzoyl isocyanate in contrast, trichloroacetyl isocyanate is reported to give only the azetidinone 376 (equation 154)27. 

Another possible synthesis is offered by the reaction of alkoxy- or aryloxysulfonylisocyanate to epichloridrine derivatives. The intermediate carbamate easily cyclises upon heating in acetone <07SC2215>. Alternatively phenyl 2-hydroxyalkyl selenides can react with benzoyl isocyanate and the final carbamate cyclize after oxidation of the selenyl functionality <07SC2693>. 

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