Synthesis of 6,6-pentamethylene-2-aminosuberic acid. A key intermediate in the synthesis of dicarba analogs of vasopressin antagonists

Polymeric Gadolinium Chelate Magnetic Resonance Imaging Contrast Agents: Design, Synthesis, and Properties

“…DOTA-tris(tert-butyl ester) activated ester (31) was designed to couple DOTA to the dendrimer via conversion of one of the four DOTA carboxylates to an amide of aminocaproic acid, thus placing the chelators at a reasonable distance from the surface of the dendrimer. Intermediate 28 was prepared from amino-ester 27 (Goodacre et al, 1977), which was prepared (Callahan et al, 1988) from 25 (Sigma). When activated ester 31 was reacted with a third generation PAMAM dendrimer, approximately 20 of the 24 surface amino groups on the dendrimer were derivatized to form the DOTA grafted dendrimer 32.…”

Preparation of Chiral Hydroxy Carbonyl Compounds and Diols by Ozonolysis of Olefinic Isoborneol and Fenchol Derivatives: Characterization of Stable Ozonides by1H-,13C-, and17O-NMR and Electrospray Ionization Mass Spectrometry

“…The allylic and homoallylic alcohols 1 ± 8, prepared from ()-camphor and (À)-fenchone, were ozonized in Et 2 O at À788 and treated with Et 3 N or LiAlH 4 to give the chiral hydroxy carbonyl compounds 9 ± 16 and the diols 17 ± 24, respectively (Scheme 1). In the case of the diols 19 and 24, the formation of new chiral centers proceeded with high diastereoselectivity.…”

“…± The cleavage of CC bonds by ozone is a very convenient route for the preparation of carbonyl compounds or alcohols depending on the reducing reagent used in a second step [1]. The ozonolysis of alkenes has been carried out in various solvents, e.g., MeOH [2], CH 2 Cl 2 [3], AcOEt [4], as well as other solvents [1]. For the synthesis of alcohols, LiAlH 4 and NaBH 4 have been usually applied in the second step.…”

A General Approach to the Asymmetric Synthesis of Unsaturated Lipidic α-Amino Acids. The First Synthesis of α-Aminoarachidonic Acid

“…Thus, we treated 8 under acidic conditions to remove the two N -Boc groups, and the resulting compound was N -Boc protected. This compound was smoothly hydrolyzed under alkaline conditions, in an almost quantitative manner, with uniform optical activity (Scheme ). To ensure the enantiomeric purity of such a product we again protected the free acid as the methyl N -Boc-α-amino ester 11 , which was then reduced to the primary alcohol 12 .…”