Walter Weyler

Rearrangement of azidoquinones IV. Ring expansion of 4-azido-1, 2-naphthoquinone

Tetrahedron Letters No,L6, pg. 1243-1246, 1969. REARRANGEMENT Pergamon Pressu OF AZIDOQUINONES IV. RING EXPANSION OF 4-AZIDO-1, Harold W. Moore, Printed in Great Britain. P-NAPHTHOQUINONE H. Raymond Shelden and Walter Weyler Jr. Department of Chemistry University of California Irvine, California 9 2664 (Received in USA 15 Januarjr 1964; received in ‘JK for publication 3 March 1969) In a previous communication’ it was shown that azido-1,4-benzo- quinones (1) undergo a highly stereoselective A a’,B -butenolides cvanoarvlidene- ring contraction (3) in concentrated sulfuric and 1,4-naphtho- to Y-cyanoalkylidene- or Y- acid (Scheme I). Scheme I Reported azidoquinone, here2 is the first example 4-azido-l, a-naphthoquinone hydroxy-benzoazepine-2,5-dione synthesis transformation hydroxy-1,4-quinones 4-Azido- which results a member to the illusive is also significant This reaction of an hydroxyazepinedione, ful synthetic precursors of an acid-catalyzed provides to the observed (4) shows the following (4) was prepared 1665 cm-‘(C=O); with concentrated nmr(CDC13):6, sulfuric characteristic s(1) which may be use- spectral acid at ambient temperature acid. in 52% yield by the reaction = CH, 7.50-8.30, high yield (82 s) The mechanism of this of alkyl- and reactions sulfuric azide with an aqueous solution of 1,2-naphthoquinone-4-sulfonic azidoquinone a convenient, ring system. with sodium azide in concentrated 1, 2-naphthoquinone of an ortho- in ring expansion to 2,5-H-4- of a class of compounds azatropolone in regards rearrangement acid, sodium salt. properties; m(4)ArH. ir (nujol): of sodium The 2120(N3), Reactionof(4) until nitrogen evolution ceased gave

Rearrangements of azidoquinones VI. Thermal rearrangement of azido-1,4-quinones to 2-cyano-1,3-cyclopentenediones

Tetralledron Letters No.45, pPO 3947-3950, 1969. Pergamon Press. Printed in Great Britain. REARRANGEMENTS OF AZIDGQUINONlB VI. THERMAL REARRANGEMENT OF AZIDO-1, I-QUINONES TO 2-CYANO-1,3-CYCLOPENTENEDIONES Harold W. Moore, Walter Weyler, Jr., and II. Raymond ShelQn Department of Chemistry University of California Irvine, California 92664 (Xeceived in USA 18 July 1969; received in UK for publication 25 August 1969) Previously it was shown that azido-1,4-quinones undergo a highly stereoselective catalyzed ring contraction to y- cyanoalkylidlne- A Q’ ’ - butenoH&s. ’ acid Reported in the present communication is an investigation of the thermal decomposition d selected azido-1,4- quinones ( 1 ), a reaction also resulting in ring contraction giving the 2-cyano-1,3-cyclopen- tenedione ( 3) ring system. This rearrangement provides a new example of a very limited number of known methods in which thermal conversion of a six to a five membered ring can be accomplished. The general structures ( 1) and ( 3) illustrate the overall chemical transformation as indicated by the following possible mechanistic scheme (Scheme I).