41764-17-4

Upstream product

• 3339-73-9 3-phthalimidopropanoic acid 
• 42406-53-1 N-phthaloyl-L-aspartic acid 
• 52096-63-6 2-<2-(Benzylthio)ethyl>-1H-isoindole-1,3(2H)-dione 

Relevant academic research and scientific papers

Exploratory studies probing the intermediacy of azomethine ylides in the photochemistry of N-phthaloyl derivatives of α-amino acids and β-amino alcohols

Exploratory photochemical studies with N-phthaloyl derivatives of glutamic acid, aspartic acid, serine, threonine and analogous carboxylic acids and alcohols have been conducted to determine the generality of azomethine ylide forming decarboxylation and retro-aldol fragmentation reactions. Preferences in the competition between these excited state reaction pathways have been determined by studies with phthalimides which contain both α-amino acid and β-aminoethanol groups.

Photochemical transformations of proteinogenic and non-proteinogenic amino acids

The photochemistry of N-activated enantiomerically pure α-amino acids is described with emphasis on chemo-, regio-, stereo-, and spin selectivity. An especially valuable chromophore is the phthalimido group. The first excited singlet states are short-lived and deactivated (chemically) via homolytic CH cleavage or (physically) via electron-transfer steps. The first excited triplet states are chemically deactivated via electron-transfer reactions and subsequent deprotonation/coupling steps. A wide variety of product types were synthesized, and potential target molecules were available by tuning the reaction conditions. Also remote groups can be activated by means of electron-transfer steps, which represents an attractive new synthetic protocol for macrocyclization.

Synthesis of Medium- and Large-Ring Compounds Initiated by Photochemical Decarboxylation of ω-Phthalimidoalkanoates

The synthesis of a variety of hydroxylactams from ω-phthalimidoalkanoates using a triplet-sensitized photodecarboxylation reaction initiated by intramolecular photo electron transfer is described. Ring sizes available by this method span from 4 (benzazepine-1,5-dione 7) to 26 (cyclodipeptide 26e). Ground-state template formation is proposed as the explanation for the high efficiency of this reaction and for the decrease in reactivity in the presence of organic bases instead of metal carbonates. The crucial step in this macrocyclization reaction seems to be the protonation of the intermediary ketyl radiais (Scheme 4). Spacer groups investigated were alkyl chains (C3-C11: 5c-h, 11a, 12), ether (16, 18), ester (20, 22), and amide (26a-f) linkages. Within the detection limits, no dimeric (= decarboxylative coupling) products were observed, indicating the high preference for intra-vs. intermolecular photoelectron transfer. The C,C radical combination step proceeds with low stereoselectivity (cf. products 11 and 12) in contrast to comparable singlet reactions. Except for the lactones 22, all products were stable under the photolysis conditions. Prolonged irradiation of 22 led to the formation of the spiro compounds 23, probably via an intermediary acyliminium betaine (Scheme 8). One serious limitation of the decarboxylative macrocyclization is its incompatibility with the glycine spacer (as in 27a and 27b), probably the consequence of a strong intramolecular H-bond (Scheme 10).

Photoelektronentransfer-induzierte Makrocyclisierung von N-Phthaloyl-ω-aminocarbonsaeuren

Stichworte: Aminosaeuren.Cyclisierungen.Makrocyclen.Photochemie

Photochemistry of the Phthalimide System, 37. - Thiazacycloalkanols by Photocyclization of S-Substituted N-(Thioalkyl)phthalimides

N-Substituted phthalimides (1,2) possessing a terminal thioether function in their side chain were irradiated with a high-pressure mercury lamp to give a variety of thiazacycloalkanol derivatives (3,7,9-13,16,17) with favored γ-, δ-, ε-, and ζ-hydrogen abstractions (Table 1), in moderate to fairly good yields.