Alkyl chloroformates

Other unsymmetrical peroxides can be prepared by this reaction by employing other acylating agents, eg, alkyl chloroformates, organosulfonyl chlorides, and carbamoyl chlorides (210). Unsymmetrical and symmetrical di(diacyl peroxides) also are obtained by the reaction of dibasic acid chlorides directiy with peroxycarboxyhc acids or monoacid chlorides directiy with diperoxycarboxyhc acids in the presence of a base (44,187,203). 

Dialkyl peroxydicarbonates (21) are produced by reaction of alkyl chloroformates with sodium peroxide (44,187) ... 

Acyl O-alkyl monopeioxycaibonates (22) aie obtained from the reaction of alkyl chloroformates with peroxycarboxyhc acids in the presence of a base (44,212) ... 

The alkyl chloroformates react with cold ethereal dispersions of the xanthates to give the fairly stable xanthogen formates. 

The A-substituted derivatives of 4-oxo-4//-pyrido[l,2-n]pyrimidine-3-carboxamides and -3-acetamides and l,6-dimethyl-4-oxo-1,6,7,8-tetrahy-dro-4//-pyrido[l,2-n]pyrimidine-3-carboxamide were prepared by treatment of the appropriate 3-carboxylic acids and acetic acid, first with an alkyl chloroformate in the presence ofNEt3 in CHCI3 below — 10°C, then with an amine (98ACH515). A-Phenethyl and A-[2-(3,4-dimethoxyphenyl)ethyl] derivatives of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetamide were obtained in the reaction of 6-methyl-6,7,8,9-tetrahydro-4//-pyrido[l,2-n]pyrimidine-3-acetic acid and phenethylamines in boiling xylene under a H2O separator. Hydrazides of 4-oxo-4//- and 4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic acid were prepared from the appropriate ester with H2NNH2 H2O in EtOH. Heating 4-oxo-4//- and 6-methyl-4-oxo-6,7,8,9-tetrahydro-4//-pyrido[l, 2-n]pyrimidine-3-acetic hydrazides in EtOH in the presence of excess Raney Ni afforded fhe appropriafe 4-oxo-6,7,8,9-fefrahydro-4//-pyrido[l,2-n]pyrimidine-3-acefa-mide. In the case of the 4-oxo-4// derivative, in addition to N-N bond... 

Thus, reduction of the Mannich reaction product (65) from acetophenone leads to alcohol 66. Replacement of the hydroxyl group by chlorine (67) followed by displacement of halogen with the anion from o-cresol affords the ether 68. Removal of one of the methyl groups on nitrogen by means of the von Braun reaction or its modem equivalent (reaction with alkyl chloroformate followed by saponification) leads to racemic 69 which is then resolved with L-(+)-mandelic acid to give the levorotary antidepressant tomoxetine (69) [16]. 

Methyl or ethyl chloroformate (70 mmol) was added dropwise to a stirred solution of a hydrazone derivative (60 mmol) of 2-amino-5-chlorobcnzophenone in a mixture of CIICI, (200 mL) and pyridine (15 mL) at 10 C. The mixture was left overnight and treated with a further amount of the alkyl chloroformate (40 mmol) and stirred at 20 C for 2 h. If /V-aryl-substituted hydrazones were used, the mixture was refluxed for 3-6 h. The mixture was poured into ice-water and the organic layer was washed successively with H2Oand 10% aq NaH0O3, dried (MgSO ) and evaporated in vacuo to yield 7 or 8 or a mixture of the two. 

The SnI mechanism is relatively rare. Another example is the decomposition of ROCOCl (alkyl chloroformates) into RCl and C02. ... 

The present procedure2 describes the conversion of resin-bound, primary aliphatic amines into isothiocyanates and the conversion of the latter into 3-aminothiophenes. The generation of isothiocyanates is related to known procedures,3 in which amines are first treated with carbon disulfide and the resulting dithiocarba-mates are desulfurized by treatment with a condensing agent (alkyl chloroformates, carbodiimides, lead or mercury salts, etc.). The presence of resin-bound isothiocyanates on the polystyrene support could be qualitatively ascertained by infrared spectroscopy (KBr-pellet strong absorption at 2091 cm-1). 

A more elaborate but general procedure for esterification involves reaction of the A-alkoxycarbonylamino acid with the alkyl chloroformate of the alcohol to be esterified in the presence of triethylamine and a catalytic amount of 4-dimethylami-nopyridine (see Section 4.19) (Figure 3.21). The product probably arises by acylation of the alcohol by the acylpyridinum ion, both originating from decomposition of the mixed anhydride. The method can be used also to prepare activated esters (see Section 2.09), though the latter are usually obtained using the common coupling techniques (see Section 7.7).47 57... 

Benzotellurophene (R = H) is stable only in benzene solution at low temperature, but the diester and disulphonyl derivatives (obtained by the bis-lithiation and subsequent reaction with alkyl chloroformates and p-toluenesulphonic anhydride) as well as the nitroderivative are more stable. 

Esters of -hydroxy- or )8-mercapto-AAs react with n-butyl isonitrile to give 5-substituted methyloxazoline (or thiazoline)-4-carboxylates in the presence of PdCla as a catalyst (74SC97). The enamine-protected AAs were also tranformed into oxazolidin-5-ones after reaction with alkyl chloroform-ates (Scheme 28) (75S724). 

The replacement of both -OH groups with chlorine produces Ccirbonyl dichloride, also known as phosgene, a useful reactant. For example, phosgene reacts with two moles of alcohol to form a dialkyl carbonate. The reaction of phosgene with one mole of alcohol produces an alkyl chloroformate, which is a useful intermediate in organic syntheses. The reaction of phosgene with four moles of ammonia yields urea and two moles of ammonium chloride, NH Cl. Figure 12-40 shows the structures of some of these compounds. 

One useful reaction utilizing alkyl chloroformate is the reaction with an amine in base to form a carbamate (urethane). Figure 12-41 illustrates this reaction. 

The preparation of furyl phosphorodichioridate is based upon a method to prepare 2-chlorofuran (16% yield, Hormi, Nasman unpublished). Later the preparation was extended to a general method to prepare furyl esters from carboxylic acid chlorides lacking a-hydrogens and alkyl furyl carbonates from primary (other than methyl) and secondary alkyl chloroformates. Phosphoryl chloride was the only acid chloride except carbon analogues found to give a furyl ester by the amine-catalyzed reaction. 

Al-(Alkoxycarbonyl) 0-(arenesulfonyl)hydroxylamines [alkyl Af-(arenesulfonyloxy) carbamates] 3i-o can be easily obtained by sulfonylation of commercially available iV-(alkoxycarbonyl)hydroxylamines (alkyl V-hydroxy carbamates). Af-(Alkoxycarbonyl) hydroxylamines can be also prepared from hydroxylamine and alkyl chloroformate . ... 

This hl-alkylated heterocycle (2) acts as the actual initiator because it is attacked rapidly under ring-opening by an oxazoline molecule, present in excess. The newly formed dimer (3) contains an ionic ring function, which is subjected to the same attack as the initiator molecule. The molecular weight of the polymers is controlled by the amount of the alkylating agent. Other suitable initiators for the polymerization of oxazolines are Lewis acids, protic acids, and alkyl chloroformates. 

Reaction with alcohol can produce two different types of products. While two molar equivalent of alcohol yields dialkyl carbonate, with one molar equivalent of alcohol the product is an alkyl chloroformate ... 

Nonionic surfactants containing a carbonate bond have been synthesized by reaction between an alkyl chloroformate and tetra(ethylene glycol), using a large excess of the latter reactant, see Fig. 11 [35]. 

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