Total Syntheses of Echitamine,Akuammiline, Rhazicine,and Pseudoakuammigine

Echitamine ( 1 ) and akuammiline ( 2 ) are representative members of a fascinating class of monoterpenoid indole alkaloids. We report the syntheses of 2 and its congener deacetylakuammiline ( 3 ). The azabicyclo[3.3.1]nonane motif was assembled through silver‐catalyzed internal alkyne cyclization, and one‐pot C?O bond cleavage/C?N bond formation furnished the pentacyclic scaffold. Compound 3 then served as a common intermediate for preparing a series of structurally diverse and synthetically challenging congeners including 1 . A position‐selective Polonovski–Potier reaction followed by formal N‐4 migration built the core of N‐demethylechitamine ( 4 ) and 1 . An alternative route featuring Meisenheimer rearrangement gave 4 as well. Oxidation of the alcohol within 3 gave rhazimal ( 5 ), which underwent tandem indolenine hydrolysis, hemiaminalization, and hemiketalization to form rhazicine ( 6 ). A sequence of N,O‐ketalization and reductive amination secured the chemoselectivity of N‐methylation, leading to pseudoakuammigine ( 7 ).     

A convenient microwave-assisted synthesis of cinchona alkaloid-derived ligands

An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.     

Streptomycindole,an Indole Alkaloid from a Marine Streptomyces sp. DA22 Associated with South China Sea Sponge Craniella australiensis

A new indole alkaloid, streptomycindole ( 1 ), and a known related compound, N‐phenylacetyl‐L ‐tryptophan ( 2 ), have been isolated from Streptomyces sp. DA22, associated with South China Sea sponge Craniella australiensis. Their structures were established on the basis of a combination of mass spectrometry, ¹H‐ and ¹³C‐NMR spectroscopic analyses, and chemical methods.     

A highly stereocontrolled asymmetric total synthesis of epimer of (+)-7-deoxypancratistatin

A highly stereocontrolled asymmetric total synthesis of epimer of (+)-7-deoxypancratistatin has been achieved from readily available starting materials via unified strategy employing Sharpless asymmetric dihydroxylation, ring closing metathesis, Overman rearrangement, hydrogenolysis and Bischler–Napieralski reaction in 15 purification steps with 15% overall yield.     

Three New Hasubanan Alkaloids from Stephania hernandifolia (Willd.) Walp.

Three new hasubanan alkaloids, hernsubanines A–C ( 1 – 3 , resp.), were isolated from the whole plants of Stephania hernandifolia. Their structures were elucidated on the basis of physical and spectroscopic data. In in vitro tests for cytotoxic activity against two human cancer cell lines, A 549 and K 562, compound 1 did not exhibit any cytotoxicity.     

The Mitsunobu reaction in the chemistry of nitrogen-containing heterocyclic compounds. The formation of heterocyclic systems (review)

Methods for the design of nitrogen-containing heterocyclic systems involving the formation of C-N bonds under the conditions of the Mitsunobu reaction are discussed. Dedicated to Afanasi Andreevich Akhrem on his 95th birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 347–385, March, 2008.