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The one-pot tandem process of ( 2R,4R,S RS )- 15 with Grignard reagents for highly diastereoselective synthesis of functionalized 2-piperidinone 1 was developed. Furthermore, the divergent syntheses of L-685,458 3 and its six analogues 20a – f have been conveniently achieved using this effective protocol as the key step.

A pseudo-five-component reaction for one-pot synthesis of polysubstituted 2-piperidinones from two equivalent aromatic aldehydes, nitromethane, ammonium acetate, and dialkyl malonates is reported. Interestingly, the formation of products was highly stereoselective. Two different stereochemical classes of polysubstituted 2-piperidinones were provided depending on the substituent position of the aromatic aldehydes.

The thermal 6-endo cyclization of N-sulfonyl-2,4-dienamide compounds to produce 4,6-disubstituted 2-piperidinone is described. The observed remarkable substituent effect due to the N-sulfonyl and C3 ethoxycarbonyl groups for acceleration of this 6-endo cyclization strongly suggests that the reaction would proceed via the 6π-azaelectrocyclization of the intermediary imidic acid. On the contrary, the corresponding 5-formyl and 5-acetyl derivatives rapidly cyclized at room temperature to produce the 5-exo cyclized products.

The cis (2a) and trans (2b) isomers of methyl 3-benzamido-2-piperidinone-6-carboxylate (Apca) were prepared and separated by fractional recrystallizations. Proton n.m.r. studies in dimethylsulfoxide solution indicate that the six-membered lactam ring adopts a distorted chair conformation with an equatorially oriented benzamido substituent in both 2a and 2b. The carboxyl function also is equatorially oriented in the trans isomer 2b, but is disposed axially in the cis isomer 2a. In the crystal structure, the six-membered lactam ring of 2a is clearly in a boat conformation with the benzamido and carboxyl functions attached to the two apex carbon atoms equatorially. The trans isomer, 2b, exists as two crystallographically independent, conformationally distinct molecules in one unit cell. The lactam ring in both molecules adopts a distorted chair conformation, as is the case in solution, with both the benazamido and carboxyl functions attached equatorially. The rotameric orientation for the endocyclic lactam differs between the two molecules. Both structures show evidence of C-H...O hydrogen bond formation intermolecularly in the solid state. This ability, along with the distinctive conformational features of Apca, may be exploitable in the design of unique features of polypeptides.

Aims To explore specific mechanisms of endophytic Pseudomonas fluorescens antagonizing Athelia rolfsii, causing southern blight of Atractylodes lancea and to evaluate the potential of this Ps. fluorescens strain to control southern blight. Methods and Results Endophytic Ps. fluorescens strain ALEB 7B isolated from A. lancea can significantly inhibit the growth of A. rolfsii strain SY4. Pre-inoculating A. lancea seedlings with Ps. fluorescens ALEB 7B reduces the southern blight morbidity rate significantly. In situ observation using scanning electron microscopy shows Ps. fluorescens ALEB 7B colonizing the plant cells. Volatile organic compounds (VOCs) from Ps. fluorescens ALEB 7B can kill A. rolfsii SY4 and dimethyl disulphide (DMDS) plays a major role. 2-Piperidinone is a unique substance having antifungal activity in dichloromethane extracts of bacterial cell-free culture filtrates. Other antagonistic mechanisms include ecological niche occupation, antibiotic production and lytic exoenzymes secretion. Conclusions Specific antagonistic mechanisms of Ps. fluorescens ALEB 7B on A. rolfsii SY4 were detailed, including release of DMDS, production of 2-piperidone, secretion of antibiotics and lytic exoenzymes and competition for spaces and nutrients. Significance and Impact of the Study This work firstly reports the significant inhibition of VOCs released by Ps. fluorescens on the growth of A. rolfsii. 2-Piperidinone is firstly found synthesized by Ps. fluorescens, having antifungal activity. This work provides an antagonistic bacterium with practical convenience and ecologically amity, which has potential for control to A. rolfsii in vitro.

Total syntheses of cepaciamides A and B were accomplished (R)-3-Amino-2-piperidinone was obtained via cyclization of (R)-ornithine. The common amide-linked fatty acid was synthesized via Sharpless AD as the key step. Amide-formation was achieved with DEPC. In the preparation of two fatty acid segments, (S)-malic acid was used as the chiral source to introduce (2S)-configuration. A known chiral cyclopropane derivative was introduced in the segment of cepaciamide A. The formation of (Z)-olefin in the segment of cepaciamide B was achieved by means of partial reduction of the acetylenic bond. Esterification between the fatty acid-segments and the amide-segment with DCC/DMAP and subsequent oxidative deprotection of the MPM group with CAN gave cepaciamides.

Total syntheses of cepaciamides A and B were accomplished. In the preparation of two fatty acid segments, ( S )-malic acid was used as a chiral source to introduce ( 2S )-configuration. A known chiral cyclopropane derivative was introduced in the segment of cepaciamide A. The formation of ( Z )-olefin in the segment of cepaciamide B was achieved by means of partial reduction of the acetylenic bond. Esterification between fatty acid segments and amide segment with DCC/DMAP and subsequent oxidative deprotection of the MPM group with CAN gave cepaciamides.

The structure of cepaciamide A was revised to be (3 R ,3′ S ,2″ S ,11″ S ,12″ R )-3-[3′-(2″-hydroxy-11″,12″-methyleneoctadecanoyloxy)hexadecamido]-2-piperidinone with respect to the absolute configuration of the C 3′- and C 2″- positions and the position of the cyclopropane ring by using synthetic methods. The structure of cepaciamide B was also determined to be (3 R ,3′ S ,2″ S ,11″ Z )-3-[3′-(2″-hydroxy-11″-octadecenoyloxy)hexadecamido]-2-piperidinone.

The structure of cepaciamide A was revised to be (3 R ,3′ S ,2″ S ,11″ S ,12″ R )-3-[3′-(2″-hydroxy-11″,12″-methyleneoctadecanoyloxy)hexadecamido]-2-piperidinone with respect to the absolute configuration of the C 3′- and C 2″- positions and the position of the cyclopropane ring by using synthetic methods. The structure of cepaciamide B was also determined to be (3 R ,3′ S ,2″ S ,11″ Z )-3-[3′-(2″-hydroxy-11″-octadecenoyloxy)hexadecamido]-2-piperidinone.

Total syntheses of cepaciamides A and B were accomplished. In the preparation of two fatty acid segments, ( S )-malic acid was used as a chiral source to introduce ( 2S )-configuration. A known chiral cyclopropane derivative was introduced in the segment of cepaciamide A. The formation of ( Z )-olefin in the segment of cepaciamide B was achieved by means of partial reduction of the acetylenic bond. Esterification between fatty acid segments and amide segment with DCC/DMAP and subsequent oxidative deprotection of the MPM group with CAN gave cepaciamides.

Total syntheses of cepaciamides A and B were accomplished (R)-3-Amino-2-piperidinone was obtained via cyclization of (R)-ornithine. The common amide-linked fatty acid was synthesized via Sharpless AD as the key step. Amide-formation was achieved with DEPC. In the preparation of two fatty acid segments, (S)-malic acid was used as the chiral source to introduce (2S)-configuration. A known chiral cyclopropane derivative was introduced in the segment of cepaciamide A. The formation of (Z)-olefin in the segment of cepaciamide B was achieved by means of partial reduction of the acetylenic bond. Esterification between the fatty acid-segments and the amide-segment with DCC/DMAP and subsequent oxidative deprotection of the MPM group with CAN gave cepaciamides.

X-ray powder diffraction data for 1-(4-Nitrophenyl)-2-piperidinone, C11H12N2O3, are reported [a = 9.514(3) Å, b = 12.308(6) Å, c = 9.175(1) Å, α = 90°, β = 91.811(2)°, γ = 90°, V = 1073.94 Å3, Z = 4, ρcal = 1.362 g cm−3 and space group P21/n]. All measured lines were indexed and are consistent with the P21/n space group. No detectable impurities were observed.

X-ray powder diffraction data for 3,3-dichloro-1-(4-nitrophenyl)-2-piperidinone, C11H10Cl2N2O3, are reported [a = 11.088(4) Å, b = 11.594(5) Å, c = 12.689(3) Å, α = 118.456(1)°, β = 100.320(3)°, γ = 107.763(3)°, V = 1259.27 Å3, Z = 4 and space group P-1 ]. All measured lines were indexed and are consistent with the P-1 space group. No detectable impurities were observed.

(±)-5-(1-Benzyloxyethyl)-6-(2-tert-butyldiphenylsilyloxyethyl)-2-piperidinone (2), a synthetic intermediate for thienamycin (1), has been synthesized stereoselectively in nine steps from methyl 2-oxo-6-endomethylbicyclo[3.1.0]hexane-1-carboxylate (3) using Lewis acid catalyzed homoconjugate addition of benzyl alcohol to 3 as a key step

The stereoselective formal synthesis of (±)-monomorine I from 6-methyl-2-piperidinone was achieved. A general method for the synthesis of ω-alkylated lactams is also described

(±)-Solenopsin A and (±)-isosolenopsin A were synthesized as a mixture in six steps from 6-methyl-2-piperidinone and they could be easily separated from each other as isomers