Chemistry of Succinylsuccinic Acid Derivatives. Part I. On the photodimerization of diethyl succinylsuccinate

Abstract

Summary. Topochemically controlled photochemical dimerization of diethyl succinylsuccinate in the solid is reported. The structure evaluation by elemental and spectroscopic analysis of the product is given. The participation of chelated enols in photochemical cycloadditions in the crystalline solid state is here demonstrated for the first time.The ground state low molecular [l] as well as macromolecular [2] chemistry of succinylsuccinic esters (1,4-dialkoxycarbonyl-2,5-dihydroxy-cyclohexa-l, 4-dienes) is well documented. Their photochemical behaviour has however received no attention until now.We found that irradiation of powdered triclinic crystals of diethyl succinylsuccinate (DESS) or of their aqueous dispersion with light of A> 260 nm, followedby Soxhlet extraction of unreacted material, gave a photoproduct according to the ollowing s cheme : OHThe production of ~nti-tricyclo[4.4.0~~~.0~~~~]-1,4,7,10-tetrae~hoxycarbonyl 3,6,9,12-tetrahydroxy-dodeca-3,9-diene in this photoreaction is the first example of dimerization of chelated enols in the solid state2) and it reaffirms the anticipated mechanism of participation of chelated enols in 2+2 cycloadditions [4]. The topochemical control [5] of the reaction is demonstrated by the absence of dimerization in solution, by the analogous solid-state dimerization of dimethyl succinylsuccinate3), as expected from its similar crystal structure [6], by contrast with the photostability3) of 1,4-diethoxycarbonyl-2,5-diamino-cyclohexa-1,4-diene [7] under the same conditions, owing to its obviously different crystal packing.Traces of diethyl-2,5-dihydroxyterephthalate were also found in the extract. Although aromatization by way of hydrogen atom abstraction from the cyclohexadiene by a photoexcited species is not unfeasible [S], this compound is believed to be a l) *) 3,Unpublished results.On leave of absence from the Weizmann Institute of Science, Rehovot, Israel. En01 dimerization in solution was only recently first reported [3].

Photodimerisation of Amidopyrine [1,2] An Example of [2+2] Photocycloaddition of an Enamine-Like Structure

“…In addition C-4, C-4' and C-5, C-5' experienced a substantial upfield shift due to the formation of the cyclobutane ring [5].…”

“…The mass spectrum at 17 mA (field-desorption method) shows the base peak mje 463 (M + H)+ as w r ell as the intense ion mje 231 (M/2)+, suggesting the symmetrical rupture of the cyclobutane ring to give fragment ions of mass equal to half of the dimer [5,6]. However, electron-impact MS gave no apparent molecular ion, but the intense ion at mje 231 and its fragmentation sequence is similar to that of the monomer 1 [7].…”

Chemistry of succinyl succinic acid derivatives. Part IV. On the hydrogenation of diethyl succinyl succinate

“…-Diethyl succinyl succinate (DESS) exists in the crystal in its enol form [2]. This reacts in the solid in a photochemical [2 + 21-cycloaddition, proving the 1,6cyclohexadiene character of the molecule [3]. The reactivity of the unsaturated moiety of succinyl succinate in its ground state has now been investigated by hydrogenation of DESS in solution2).…”

“…absorption at l .~~H = 2 5 0 nm (c = 9500). As DESS absorbs in the same region with E = 20,000 [3], this hydrogenation product must have lost half of the original light-absorbing chromophores. By TR., NMR.…”

Crystal and molecular structure of cis,anti,cis-N,N′-dibenzoyl-3,12-diazatricyclo[6.4.0.02,7]dodecan-6,12-dione and cis,anti,cis-N,N′-dibenzoyl-3,9-diazatricyclo[6.4.0.02,7]dodecan-6,9-dione. Photodimers of N-benzoylcyclohex-2-ene-4-one

“…ture on the photochemical [2 + 21 cycloaddition dimerization reactions of a,P-unsaturated carbonyl Crystal structure of 2 compounds both in solution (1, 2) and in the solid Crystal data state (3)(4)(5). The photochemical reactions of enam-C24H22N204 fw = 402.24 ides and dienamides have also been extensively Monoclinic P2,/c, a = 18.568(4), b = 11.396(4), c studied (6).…”