diethanolg were isolated in small amounts as byproducts, the quantities increasing when the excess of aminobutanol was decreased. An interesting alternative synthesis, reductive alkylation of 2aminobutanol with glyoxal using sodium borohydride1° as reducing agent, gave good yields. This work has shown that in mice the dextro form of 2,2’-(ethylenediimino)-di-l-butanolis more active and less toxic than streptomycin when administered parenterally and possesses an oral efficacy index (ratio of maximum tolerated dose to median effective dose) a t least equivalent to that of isoniazid. -4 series of papers is in preparation covering studies of numerous homologs and of various analogs and modifications of the functional groups of this chemotherapeutic agent.
I
I
R
R
IIIa, R = CsHj b,R-H
I r a , R = CBH, b, R = H
IIIa
CHIODf
,/CocBH5
(9) meso-Dihydrochloride, m.p. 246.5-247.5O dec. (&)-dihydrochloride, m.p. 238-239’ dec. (10) J . H. Billman and A. C. Diesing, J . Org. Chem., 22, 1068 (1957). used this reagent for reduction of aromatic Schiff bases.
LEDERLE LABORATORIES DIVISIO?; R. G. WILKINSOS ORGANIC CHEMICAL RESEARCH R. G. SHEPHERD AMERICAS CYANAMID COMPANY J. P. THOMAS EXPERWEXTAL THERAPEUTICS RESEARCH C. BAUCHX PEARL RIVER,XEWI’ORK RECEIVED MARCH24, 1961 C-C02CH3
A NEW PHOTOCHEMICAL PRIMARY PROCESS, THE PHOTOCHEMICAL ENOLIZATION OF O-SUBSTITUTED BENZOPHENONES Sir :
V
and dimethyl acetylenedicarboxylate (0.06 mole) We wish to report a new type of photochemical in benzene was irradiated with a Hanovia S-SO0 primary process, the photochemical enolization of source a t 15-20’ for 24 hours. After the solvent o-substituted benzophenones. Benzophenone was removed, the residue crystallized and no apreadily is reduced photochemically in the presence preciable amount of polymeric material was formed. of hydrogen donors to give benzopinacol cia a ketyl The residue was recrystallized from benzene-cycloradical intermediate (I). Photochemical pinacol hexane to give I V in 85% yjeld (m.p. 112’; found: reduction is suppressed completely and no ketyl C, 71.25; H, 5.36; A,, 3300 cm.-’, 1 i 2 0 a n . - ‘ ; radical formation is detected if the benzophenone is strong ultraviolet end absorption). The structure substituted a t the ortho position by an alkyl group of IV was established by its conversion to l-phenylcontaining an a-hydrogen. Instead, o-alkylbenzo- naphthalene-2,3-dicarboxylicacid (V) , identical in phenone (11) undergoes intramolecular hydrogen all respects with an authentic sample.3 The quantransfer to give the corresponding enol under the tum yield of this photochemical addition is estiinfluence of ultraviolet light. Photochemical mated a t >0.5. The generality and further apenolization of this type has been demonstrated plications of this reaction are being investigated. unequivocally by these observations. The authors wish to thank Professor 11‘. -1. o-Benzylbenzophenone (IIa) is extremely stable Noyes, Jr., for some valuable discussion and LIr. toward ultraviolet radiation generated by either Richard Atkinson for his assistance in the preparalow pressure or high pressure mercury arcs. The tion of an authentic sample of IT. C. R. is incompound was recovered unchanged after pro- debted to the Petroleum Research Foundation longed irradiation in alcohol solutions and no for a graduate fellowship. pinacol could be detected. When a solution of ( 3 ) A. Michael, Be?., 39, 101% (1906). IIa in CH30D was irradiated with a Hanovia S-200 (4) Alfred P. Sloan Fellow. source, the recovered I I a was found to contain DEPARTMENT OF CHEMISTRY 1.04-1.09 atoms of deuterium per molecule,2 while UNIVERSITY OF CHICAGO x.c . Y A S C 4 no deuterium incorporation took place when the CHICAGO 37, ILLINOIS CARLOS RIVAS same solution was allowed to stand a t ordinary RECEIVED FEBRUARY 27, 1961 laboratory conditions. By n.m.r. spectrometry, all the deuterium atoms were found to be located THE PHOTOCHEMICAL REARRANGEMENT OF a t the benzylic position. HYPOCHLORITES The photo-enol (IIIb) of o-methylbenzophenone Sir : (IIb) reacts smoothly with dimethyl acetyleneI n a recent communication’ we adumbrated a dicarboxylate, a dienophile, to give an adduct (IV) in excellent yield. An equimolar solution of IIb photochemically induced rearrangement of hypohalites of the general type (A) + (B) (X = halo(1) C. S Hammond and W.M. Moore, J . A m . Chem. SOC.,81, 6334 (1959), and references therein. (2) Deuterium analysis by Dr. Josef Semeth of Urbana, Illinois.
(1) D. H. R. Barton, J. M. Beaton, L. E. Geller and M. M. Pechet,
J. A m . Chem. Soc., 82, 2640 (1960).
