Chloroform, direct reaction with

Phenoselenazines can be synthesized from diarylamines by direct reaction with diselenium dichloride in chloroform <70CCA6i > phenoselenazine itself (176) is obtained in this way from diphenylamine <59JOC37>. Y-Alkyl phenoselenazines can be prepared in a similar way from 7V-alkyldiphenylamines, or by A-alkylation of phenoselenazine (see Section 6.24.7.2.1). 

With enamines of cyclic ketones direct C alkylation occurs with allyl and propargyl as well as alkyl halides. The reaction is again sensitive to the polarity of the solvent (29). The pyrrolidine enamine of cyclohexanone on reaction with ethyl iodide in dioxane gave 25% of 2-ethylcyclohexanone on hydrolysis, while in chloroform the yield was increased to 32%. 

In a typical synthesis, reduction of the nitro group in starting material 1 leads to the corresponding diamine 1. Reaction with intermediate 12 obtained by acylation of the methyl ether of thiourea with methyl chloroformate, leads directly to fenbendazole (78). ... 

The reaction of arylthioamides (248) with phenylisocyanate affords the arenethiocarboxamide (249), which can be benzylated to give (250) and then converted into 5-aryl-3-oxo-2-phenyl-1,2,4-thiadiazoline (251) on treatment with bromine in chloroform. Alternatively, (249) can be transformed into (251) by direct oxidation with bromine (Scheme 56) <85IJC(B)977>. 

The older and currently less used production method for dichloromethane involves direct reaction of excess methane with chlorine at high temperatures (400-500°C), or at somewhat lower temperatures either catalytically or photolytically. Methyl chloride, chloroform and carbon tetrachloride are also produced as co-products (Rossberg et al., 1986 Holbrook, 1993). 

Dihydro allyl adducts like (254) are obtained by reaction of thiazoles with allyltributyl tin in the presence of alkyl chloroformates acting as activators of the thiazole ring (Scheme 28) (94JOC1319). This reaction most likely takes place via the intermediate azolium salt. Under these conditions even organolithium compounds can add to thiazoles (84TL3633). Similarly, direct ethynylation of thiazole and benzothiazole can be achieved by reaction with bis(tributylstannyl)acetylene (Scheme 29) (94SL557). 

The magnesium bromide salt of indole gives the 3-carboxy derivatives in about 30% yield on reaction with carbon dioxide (56JCS2853). Ethyl indole-3-carboxylate can be obtained directly, but in modest yield, using ethyl chloroformate (62JOC496, 6602805). Indole-2-carboxylic acid derivatives can be obtained via the benzenesulfonyl-protected 2-lithio derivative (equation 181) (73JOC3324). 

Carbamate-bound guanidines have been prepared by the condensation of amines with thioureas linked to insoluble supports as carbamates [519]. The direct reaction of guanidines with resin-bound carbonates or other alkoxycarbonylating agents requires the use of chloroformates or other reactive carbonic acid derivatives [520,521], Carbamate-bound amidines (Entries 7 and 8, Table 3.28) have been prepared by the reaction of amidines with resin-bound 4-nitrophenyl carbonates (0.9 mol/L amidine in DMF/DIPEA, > 4 h [522-524]). 

Bilirubin is a lipid-soluble substance and for it to give a direct van den Bergh reaction it must be converted into a water-soluble state. This can be achieved in alkaline solution or by the use of solvents, such as ethanol, which are soluble in both water and chloroform (Cl). Conjugation with glucuronic acid also causes the solubilization of bilirubin and in view of the well-known versatility of the liver s detoxifying systems, the possibility that bilirubin may be conjugated with other substances has been considered. 

JAP(K)242587], The latter compounds were also obtained directly from carboxamides 31 by reaction with 2-chloroethyl chloroformate followed by treatment with ethanolic potassium hydroxide (89H985). 

Bis(iodosyl)benzene reacted with triflic anhydride to afford a bis iodine (III) derivative [21], DIB or iodosylbenzene, however, do not afford with triflic acid, or its anhydride, the expected analogues of HTI, although these are initially formed. The reaction of iodosylbenzene and triflic anhydride leads to two different products, depending on reaction time. When triflic acid was allowed to react with iodosylbenzene in dichloromethane for about 20 min the yellow p-compound 1 (m.p. 100-110°C) was obtained it was the same with the so-called Zefirov s reagent, which was originally prepared from DIB and triflic acid in chloroform. When the reaction time was extended to 12 h, then 1 isomerized to the slightly pale yellow compound 2 (m.p. 125-132°C). For preparative purposes the direct reaction of iodosylbenzene with triflic acid was preferable for 2, since it was isolated in 94% yield. 

N-Tritylamino acids. Direct reaction of trityl chloride with amino acids provides N-trityl derivatives in low yield. A superior route to these derivatives involves reaction of trimethylsilyl esters of N-trimethylsilylamino acids with trityl chloride in refluxing chloroform, which provides the N-protected amino acids in 88-92% yield. Trimethylsilyl-protected hydroxyl or thiol groups are not cleaved under these conditions.1... 

Symmetrical divinyllead diacetates can be obtained directly from the corresponding vinylboronic compound through reaction with lead tetraacetate in chloroform at room temperature. Thus, the reaction of (E)-styrylboronic acid 59 with lead tetraacetate in chloroform afforded the bis-(/. )-styryllead diacetate 60 and the reaction of ( )-hex-l-enylboronic acid 61 led to the relatively unstable bis-[fE)-hex-l-enyl]lead diacetate 62 (Equations (54) and (55)). 

Although the direct reaction of elemental silicon with alkyl chlorides has been extensively studied and a vast number of reports are available in the literature, the reactions with polychlorinated alkanes such as methylene chloride and chloroform are scarce, possibility due to the intractability of the non-volatile high molecular weight products often obtained. 

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