Isocyanate, chlorosulfonyl

Chlorosulfonyl isocyanate has been used to introduce 3-carboxamide groups. The initial product, an A -chlorosulfonylcarboxamide, is treated with tri-n-butylstannanc to form the primary carboxamide[15], 3-Cyano groups can also be introduced using chlorosulfonyl isocyanate. The intermediate N-chlorosulfonylindole-3-carboxamide is converted to 3-cyanoindole on reaction with triethylamine[16] or DMF[17],... 

Chlorosulfonyl isocyanate is an excellent alternative to alkaline cyanates ia the preparation of hydantoias from stericaHy hindered or labile amino nitriles (62). Imino derivatives similar to (18) can also be obtained by addition of sonitnles to imines followed by treatment with a cyanate (63). 

Fig. 7. Synthesis of monocarbams where P is an amino protecting group and CSI is chlorosulfonyl isocyanate. TFA is trifluoroacetic acid...

AT-Unsubstituted azetidin-2-ones are versatile intermediates in the preparation of a variety of novel /3-lactam containing systems. They are usually made either by reductive dechlorosulfonylation of alkene/chlorosulfonyl isocyanate cycloadducts cf. Section 5.09.3.3.2), which... 

Woodward s synthesis, 4, 416-419 Chlorophyll b, 4, 382 Chlorophyll c, 4, 382 Chlorophyll d, 4, 382 Chlorophylls, 4, 378 biosynthesis reviews, 1, 99 structure, 4, 370 substituents reactions, 4, 402 Chloroporphyrin e, 4, 404 Chloroprothixene pharmacology, 3, 942 Chloropyramine as antihistamine, 1, 177 Chloropyrifos synthesis, 2, 201 Chloropyrifos-ethyl as insecticide, 2, 516 Chloropyrifos-methyl as insecticide, 2, 516 Chloroquine, 1, 145 adsorption on nucleic acids, 1, 179 as antimalarial, 1, 173, 2, 517 Chloroquine, hydroxy-as antimalarial, 2, 517 Chlorosulfonyl isocyanate cycloaddition reactions... 

Addition, chloroform, to olefins to form 1,1,3 tnchloroalkanes, 46, 106 chlorosulfonyl isocyanate to isobutylene to give 0-isovaleiolactam-N-sulfonyl chloride, 46, SI cyclohexyl amine to silicon tetraiso-cyanate, 46, 69... 

In contrast, addition of dimethyl acetylenedicarboxylate to cyclopent[6]azepine (6) is slow and furnishes, in 53% yield, a mixture of the dimeric 1 2 adduct 7 (red crystals), the 1 3 adduct 8 (yellow oil), and an unidentified purple oil.2 Surprisingly, cyclopent[6]azcpine fails to react with other common dienophiles such as ethenetetracarbonitrile, diethyl maleate and chlorosulfonyl isocyanate. 

Substituted azocine systems are much more stable than the parent compound, and 2-methoxy derivatives have been intensively examined. Starting from cyclohexa-1,4-diene (3), a [2 + 2] cycloaddition with chlorosulfonyl isocyanate, followed by removal of the chlorosulfonyl group, leads to the /3-lactam 4, which can be transformed by O-methylation with Meerwein s salt into the corresponding imidate. Monobromination with A-bromosuccinimide and subsequent treatment with base results in a methoxyazabicyclo[4.2.0]octatriene derivative, which spontaneously isomerizes to 2-methoxyazocine (5).13,14... 

Heterocyclization of chlorosulfonyl isocyanate with ethyl-3-oxo-2-(arylhydrazono)butanoates 1011 (2 1) gave thiadiazolotriazinediones 1012 (91H1517) (Scheme 188). 

Caution Chlorosulfonyl isocyanate, is highly corrosive. This preparation should be carried out in an efficient hood, and rubber gloves should be worn during the first step. 

The preparation of chlorosulfonyl isocyanate is described in Org. Syn., Coll. Vol. 5, 226 (1973). This compound is highly corrosive, reacts explosively with water, and may be contaminated with cyanogen chloride. 

The water bath should not be positioned around the flask until after the solution of chlorosulfonyl isocyanate has been added. 

The reactive compound chlorosulfonyl isocyanate (ClSOaNCO, forms P-lactams even with unactivated alkenes, as well as with imines, allenes, conjugated dienes, and cyclopropenes. With microwave irradiation, alkyl isocyanates also... 

Figure 4C. Chromatogram illustrating the studies conducted on the enzymatic conversion of the PSP toxins to decarbamoyl metabolites (appended with an "M" in these figures). HPLC was used to confirm that the toxin metabolites (labeled "M") were the decarbamoyl form through conversion back to the carbamate form with chlorosulfonyl isocyanate. (See Ref. 15 for HPLC conditions.)...

Aminosulfonyl ureas were constructed from a sulfonylcarbamate linkage (Scheme 31) [72], Reaction of chlorosulfonyl isocyanate (CSI) with Wang resin provided a chlorosulfonylcarbamate 63 which was then converted to substituted amino sulfonylcarbamate compounds by reaction with excess amines. The final aminosulfonyl urea products were cleaved from the resin by treatment with amines in HF at reflux temperature for overnight. 

The nitrogen atoms in ADC compounds are highly electrophilic. Nucleophilic attack on nitrogen is easy, and as with electrophilic acetylenes, such as dimethyl acetylenedicarboxylate, it seems likely that some cycloaddition reactions of ADC compounds with unsymmetrical substrates proceed via a stepwise mechanism. PTAD is a powerful electrophile, although TCNE is more reactive, and chlorosulfonyl isocyanate is more reactive still.58... 

The triazino-oxathiazines 559 were prepared by cyclocondensation of phenylhydrazone derivatives 558 with chlorosulfonyl isocyanate. The formation of 559 was dependent on the substituents (9ISC 1695). 

Oxaziridines 381 have been reacted with chlorosulfonyl isocyanate (Scheme 65), this time forming 1,2,4-oxadiazolidin-3-ones 382 via C-N bond cleavage. The structure of the product was established by X-ray crystallography as the 3-one rather than the 5-one that might be expected on the basis of the chemistry shown in... 

---