Benzoyl chloride, benzamide prepared preparation

Prepared by the dehydration of benzamide. Hydrolysed by dilute acids and alkalis to benzoic acid. Good solvent. benzopheDone,C]3HioO,PhC(0)Ph. Colourless rhombic prisms, m.p. 49 C, b.p. 306°C. Characteristic smell. It is prepared by the action of benzoyl chloride upon benzene in the presence of aluminium chloride (Friedel-Crafts reaction) or by the oxidation of di-phenylmethane. It is much used in perfumery. Forms a kelyl with sodium. 

Carry out this preparation in precisely the same way as the above preparation of oxamide, using 2 ml. (2-4 g.) of benzoyl chloride instead of the ethyl oxalate, and observing the same precautions. Considerably more heat is generated in this reaction therefore hold the cork very securely in position during the shaking. After vigorous shaking for 15 minutes, no trace of oily benzoyl chloride remains. Filter off the fine flakes of benzamide, wash with cold water, and then recrystallise from hot water yield, 1-5 g. Colourless crystals, m.p. 130°. 

Benzamide may also be prepared by adding 5 gms. benzoyl chloride drop by drop to 20 c.cs. cone, ammonia solution. 

Place 45 g (0.37 mol) of benzamide (prepared from benzoyl chloride, cf. Expt 5.154) and 80 g (0.56 mol) of phosphorus pentoxide in a 250-ml round-bottomed flask (for exact experimental details on the handling and weighing out of phosphoric oxide, see isobutyronitrile, Expt 5.160). Mix well. Fit the flask with a Claisen distillation head (Fig. 2.13(c)) and distil under reduced pressure using a water pump with an air leak in the system so that a pressure of about 100 mmHg is attained. Heat the flask with a free flame until no more liquid distils the nitrile will pass over at 126-130 °C/100 mmHg. Wash the distillate with a little sodium carbonate solution, then with water, and dry over anhydrous calcium chloride or magnesium sulphate. Distil under normal pressure from a 50-ml flask the benzonitrile passes over as a colourless liquid at 188-189 °C. The yield is 28 g (74%). The i.r. spectrum of benzonitrile is shown in Fig. 3.39. 

C) Preparation of Benzamide (Sm.). Perform the experiment in the hood. Place 5 g of ammonium carbonate in a mortar and pulverize well. Add 2 ml of benzoyl chloride and mix with the pestle for a few minutes. Add 2 ml of concentrated aqueous ammonia, and allow to stand for 10 minutes. Transfer the reaction mixture... 

An example is as follows. After protection as a silyl ether, amidation of benzyl A-(5,6-0-isopropylidene-4-hydroxycyclohex-2-enyl)carbamate 229 (prepared from 3-bromo-lS,2S-0-isopropylidenecyclohexa-3,5-diene) with (6-bromo-3,4-methylenedioxy)benzoyl chloride gave the protected N-benzyloxycarbonyl-A-(cyclohex-2-enyl)benzamide 230. A modified Heck reaction of 230 in anisole produced the protected lycoricidine 231 in 27% yield (two steps) by A-detosylation. Acid treatment of 231 provided (-H)-lycoricidine (204) in 85% yield (Scheme 22). 

Benzohydroxamic acid has been prepared by the action oi hydroxylamine on benzoyl chloride,2 ethyl benzoate,1,3 or benzamide.4... 

Base-catalyzed cyclization of A -benzoyl-a-chloroacetamide is a classical method used to prepare 2-phenyl-4(5//)-oxazolone. Extension of this methodology to the A -aroylcinnamides 35 afforded a series of 5-arylidene analogues 37 albeit in unstated yield (Scheme 6.12). " Thus, acylation of the sodium salt of a benzamide with a cinnamoyl chloride gave the imides 35 that were converted to 36 via a bromination-dehydrobromination sequence. Cyclization to 37 was affected with sodium hydride in 1,2-dimethoxyethane (DME). The authors noted that catalytic reduction of 37 afforded the 5-(arylidene)oxazolidine from which 37 could be regenerated in the presence of air. 

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