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f.N4
suction filtration and crystallized once with 25 cc. of 2 : l benzene-alcohol; 1.1 g. of faintly yellow crystals melting 174 -17fi', 52% of the theoretical. Anal. Calcd. for C Z ~ H ~ ~ O & S C1, Z : 1.5 8 , mol. wt., 447 2. Fouud: Cl, 15.4; mol. wt., 425, 1-87 When the carbinol and 3,5-dinitrobenzoyl chloride were allowed to react without pyridine as a solvent, di-(p,p'dichlorobenzohydryl) rther, m p 120-1 23", was obtained.2 - .__ 21 (:nirnmllt and BucL 1 I i l h
rULIKUAL
67, 693 $ l 1 b i j I
Vol. 67
Determination of the molecular weight of the 3,5-dinitrobenzoate ebullioscopically in benzene consistently gave values ranging from 1.5-2times the theoretical, indicating that association probably had *occurred. The reported values were obtained with acetone as the solvent: SHERWIN-WILLIAMS LABORATORY OLIVERGRUMMXTT WESTERN RESERVE UNIVERSITY ALLENBUCK RUTHJOSEPH CLEVF,LhND,OH10 RECEIVED JANUARY 20, 1945
COMMUNICATIONS T O T H E EDITOR FURAN AND TETRAHYDROFURAN DERIVATIVES. IV. THE SYRTHESIS OF " Y D R O - 2 - O X O - 1 FUR0 [3,4 ]IMIDAZOLE DERIVATIVES
hydro-2-oxo-1-fur0[3,4]imidazoles. This novel procedure represents a convenient way to prepare derivatives of this new class of compounds. Sir : Hydrogenation of 3,4-diaminocarbethoxy-2In a search for convenient methods to synthesize furanpentanoll followed by mild alkaline treatbiotin-like compounds, a number of 3,4-diamino- ment gave a hexahydro-2-oxo-1-furo[3,4)carbethoxyfurans have recently been prepared. imidazole-4-pentanol isomer, m. p. 152-153'. It has now been observed that low pressure (Anal. Calcd. for C10H1803N2:C, 56.07; H, 8.47; hydrogenation converts these substances into the N, 13.07. Found: C, 56.06; H, 8.18; N, 12.90), corresponding tetrahydro derivatives. Thus, cata- which on oxidation was converted into the correlytic hydrogenation of 3,4-diaminocarbethoxy-2- sponding hexahydro-2-oxo-1-furo [3,4]imidazole-4methylfuran under conditions which favor cis valeric acid (I), m. p. 208-210°. (Anal. Calcd. addition of hydrogen gave a cis 3,4-diaminocarb- for C10H1804N2: C, 52.63; H, 7.0'7; N, 12.27. ethoxy-%methyltetrahydrofuran isomer, m. p. Found: C, 52.67; H, 7.43; N , 12.12.) Com95-96'. (Anal. Calcd. for CllHzoOaNz: C, 50.75; pound (I) represents one of the oxygen analogs H, 7.74; N, 10.75; OCzHs, 34.62. Found: C, of biotin. Further work which is a t present under 50.80; H, 7.79; N, 10;68; OCzHs, 34.87.) Mild way will demonstrate the stereochemical relationhydrolysis of this substance with dilute barium ships between this new compound and biotin. hydroxide resulted in a ring closure and a hexa0 hydro-2-oxo-4-methyl-l-furo [3,4]imidazole isoII mer, m. p. 234-236', was obtained. (Anal. Calcd. for CCH1002N2: C, 50.71; H, 7.09; X, 19.70. Found: C, 51.11; H, 7.26; N, 19.38.) The structure of this compound was established " H?C\ " /HC-CH~-CHi-CHz-CHz-COOH ' by drastic hydrolysis with barium hydroxide a t 130-140' for twenty hours, which opened the 0 urea ring with the formation of the corresponding ( I1 cis-3,4-diamino-2-methyltetrahydrofuran, isolated I I E P A R T M E N r OF C H h M I S r R ! ;is the crystalline sulfate, 111. p. 2iO-2i5'. (Anal. LTLIVERSIT\ OF PITTSBURGH PENNSYLVANIA K L A I ~ SH ~ F M A Y N Calcd. for CsH140~N&3:C, 28.03; H,6.59; N , PITTSBURGH, R ~ C L I V EhLl )~ ~ c9,i i1043 13.Oi; S, 13.97. Found: C, 27.82; H, (i.36; N , 12.89; S, 15.35.j Treatment of the abovc diamine sulfate with phosgene in sodium bicarIN THE TERPENE SERIES. 11.' HYDRObonate solution gave a hexahydro-2-oxo-4-methyl- STUDIES GEN DISPROPORTIONATION OF LIMONENE 1-furo[3,4]imidazole, m. p. 234-236'. (Anal. Sir: Calcd. for CCH1002N2: N, 19.70. Found: N , During the study of bromination of terpenic 20.03), which by mixed melting point was found i t was noticed that the unreacted hydrocarbons to be identical with the starting material. The above described reactions demonstrate terpenes contained a large amount of aromatic that cis-3,4-diaminocarbethoxy-2 substituted hydrocarbons. On further investigation it was tetrahydrofurans on treatment with dilute barium found that a small amount of organic bromides hydroxide undergo ring closure to form hexa- admixed with d-limonene caused hydrogen transfer to occur during the process of distillation, I'
i
( 1 ) Hofmann and Bridgwater, THIS JOURNAL, in press. (2) The desirnation cis indicates the position of theamino groups. The steric position of the side chain is not established.
I
( 1 ) For Paper I of this series, see V. N. Ipatieff and H. Pines. 66, 1120 (1944)
T H r s JOUKHAL,
