The ionization constants of seven isoureas have been measured. The values for simple alkyl isoureas increase definitely from methyl to n-propyl, the n-butyl-isourea showing no further increase. Isobutyl-isourea has a decidedly greater constant than the n-butyl compound. Introduction of the phenyl group into ethyl-isourea lowers the value of the constant as would be expected. The presence of a double bond in the radical also produces a similar effect as shown by a comparison of the values for n-propyl- and allyl-isoureas. Cyclohexyl-isourea has a constant slightly higher than those of n-propyl and n-butyl-isoureas. Some comparison with a series of primary amines is made.
In this investigation a series of new iso-urea ethers has been prepared by the general reaction of addition of alcohols to cyanamide in the presence of dry hydrogen chloride. Where the hydrochlorides of the iso-ureas were difficult to isolate and purify, conversion to the salicylates gave excellent results. The new iso-ureas were further characterized by condensing them with methyl malonate to form iso-urea salts of 2-alkoxy-barbituric acids, from which the acids themselves could be easily liberated by the addition of dilute mineral acid. A few open-chain acyl derivatives were also prepared.
As part of a study of the chemistry and pharmacology of urethans, a number of substituted urethans have been prepared in this Laboratory, and it seemed desirable to record those that have not previously been described in the literature, and to describe improved or modified methods of preparation for some that have been reported already.These compounds have been prepared (1) by treating a solution of an amine in ether or benzene with the required amount of alkyl chlorocarbonate in the presence of an aqueous solution of sodium or potassium hydroxide, or (2) by heating together an amino compound and an alkyl chlorocarbonate with or without a solvent, or (3) by heating together a urethan with an acid chloride with or without a solvent.Preliminary observations on the pharmacological properties of some of these compounds are included in this paper but detailed studies will be reported elsewhere.
The reaction between acetamide and alkyl bromides, showing its general applicability to the synthesis of substituted acetamides and the corresponding amines, has been investigated.A possible mechanism for the reaction, accounting for the production of ammonium bromide, has been suggested.1. 2.During a study of the pharmacological properties of some iso-urea derivatives, it was found by one of us1 that carbethoxy-ethyl-isourea had well-marked physiological action, the chief effects being a mild central depression, a rapid and considerable fall of body temperature, and an increased muscle tonus. The muscular hypertonus suggested an action similar to that of guanidine which is known to stimulate the myo-neural receptors2It was decided for the purpose of a comparative study to prepare the mono-and dicarbethoxy-guanidines (guanidine mono-and di-formic esters) and examine their pharmacological properties. At the same time it was thought desirable to prepare the dicarbethoxy-ethyl-iso-urea, to determine the effect of introducing a second carbethoxy group into the iso-urea molecule. The compounds may be regarded as urethans, and the study of them is therefore included in a series of studies being carried on in this Laboratory on the chemistry and pharmacology of some mono-and diurethans. Formulas I and I1 show the structures of the iso-urea derivatives and I11 and IV the structures of the carbethoxy-guanidines. /NH.COOC*Hs C-OCeH5 ~N H /NH.COOCzHb \N.COOC~HB C-OCzH5
In continuation of earlier studies on the formation of alkyl-isoureas by the addition of alcohols to cyanamide, a series of new isoureas has been prepared from ethylene glycol, glycol mono-ethyl ether, glycol mono-acetate, ethyl glycollate, ethanolamine, and resorcinol. In addition, the preparation of allyl-isourea, which had previously failed, m-nitrobenzyl- and cyclohexyl-isoureas was accomplished. The new isoureas were characterized by the preparation of salts (salicylates or benzoates), and of cyclic isoureides by condensation with acetoacetic and malonic esters. Some further study was made of benzyl- and phenylethyl-isoureas, previously prepared in this laboratory.
ACYL t JO-UREAS 3177 specific rotational values of these halogen derivatives shows that these straight chain biose derivatives behave the same as the branched chain biose derivatives investigated in the previous article, as agreement with the regular relationship observed for the corresponding derivatives of the monose sugars is obtained only by excluding the values for the fluoro derivatives.Besides the pure -halogen derivatives of gentiobiose, impure ß-chloro and iodo compounds were obtained.The Walden inversion from ß-octa-acetylgentiobiose to -chloroand iodo-hepta-acetyl gentiobiose by the action of hydrochloric and hydriodic acids proceeds at least in two definite steps, ß-chloro-or iodo-hepta-acetylgentiobiose being intermediately formed.
The study of the action of ammonia and amines on acyl urethanes has been extended to urethanes of monobasic acids in order to determine whether the rule tentatively formulated with respect to the diurethanes (2, p. 361) holds for the monourethanes. The results reported here provide considerable evidence that the rule is broadly true, the tendency for formation of acid amides or ureas varying with the strengths of the acids and bases involved.
The ionization constants of p-nitrophenylacetic and phenylmalonic acids have been determined from conductivity data. The value of K for p-nitrophenylacetic acid at 25 °C. is 1.04 × 10−4, about twice that of phenylacetic acid. The nitro group in the nucleus has not as powerful an effect on the ionization when the COOH group is in the side chain as it has when both nitro group and COOH are in the nucleus. K for p-nitrobenzoic acid is six times as great as K for benzoic acid. K for phenylmalonic acid is 2. 77 × 10−3 as compared with 1.6 × 10−3 for malonic acid.
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