Laurencia nipponica

Abe, T., Masuda, M., Suzuki, T. and Suzuki, M. 1999. Chemical races in the red alga Laurencia nipponica (Rhodomelaceae, Ceramales) Phycol. Res. 47 87-95. 

Fukuzawa A, Masamune T (1981) Laurepinnacin and isolaurepinnacin, new acetylenic cyclic ethers from the marine red alga Laurenciapinnata Yamada. Tetrahedron Lett 22 4081 1084 Fukuzawa A, Kurosawa E, Tobetsu I (1979) Constituents of marine plants. XXXVI. Laurallene, new bromoallene from the marine red alga Laurencia nipponica yamada. Tetrahedron Lett 30 2797-2780... 

The bromoallene (-)-kumausallene (62) was isolated in 1983 from the red alga Laurencia nipponica Yamada [64a], The synthesis of the racemic natural product by Overman and co-workers once again employed the SN2 -substitution of a propargyl mesylate with lithium dibromocuprate (Scheme 18.22) [79]. Thus, starting from the unsymmetrically substituted 2,6-dioxabicyclo[3.3.0]octane derivative 69, the first side chain was introduced by Swern oxidation and subsequent Sakurai reaction with the allylsilane 70. The resulting alcohol 71 was protected and the second side chain was attached via diastereoselective addition of a titanium acetylide. The synthesis was concluded by the introduction of two bromine atoms anti-selective S -substitution of the bulky propargyl mesylate 72 was followed by Appel bromination (tetrabromo-methane-triphenylphosphine) of the alcohol derived from deprotection of the bromoallene 73. 

During this investigation the authors discovered that their earlier proposed structure of epilaurallene must be incorrect. A new isomer of pannosallene, nipponallene (671), along with the novel neonipponallene (672) was isolated from Laurencia nipponica collected off the Russian shore of the Sea of Japan... 

Laurencia nipponica (790), and the structure and absolute configuration were confirmed by total synthesis (791). This new compound is a stereoisomer of the known (3Z)-isoprelaurefucin. A Malaysian Laurencia pannosa has yielded (3Z)-chlorofucin (698) (578), and (3Z)-bromofucin (699), which is also a new C15-acetogenin, is found in a South African sea hare, Aplysia parvula (792). The (3 )-neoisoprelaurefucin (700) was found in Laurencia obtusa collected in Turkish waters (557). 

Masuda M, Abe T, Sato S, Suzuki T, Suzuki M (1997) Diversity of Halogenated Secondary Metabolites in the Red Alga Laurencia nipponica (Rhodomelaceae, Ceramiales). J Phycol 33 196... 

Lyakhova EG, Kalinovsky AI, Kolesnikova SA, Vaskovsky VE, Stonik VA (2004) Halo-genated Diterpenoids from the Red Alga Laurencia nipponica. Phytochemistry 65 2527... 

Suzuki M, Mizuno Y, Matsuo Y, Masuda M (1996) Neoisoprelaurefucin, a Halogenated Ci5 Non-Terpenoid Compound from Laurencia nipponica. Phytochemistry 43 121... 

Suzuki, T. and Kurosawa, E. (1979) New bromo acetal from the marine alga, Laurencia nipponica Yamada. 1. Chemistry Letters, 301—304. 

A. I. Usov and M. Ya. Elashvili, Polysaccharides of algae. 44. Investigation of sulfated galactan from Laurencia nipponica Yamada (Rhodophyta, Rhodomelaceae) using partial reductive hydrolysis, Bot. Mar., 34 (1991) 553-560. 

Last year the unusual structure of laureacetal-A (138) was reported. A further examination of Laurencia nipponica Yamada has revealed another closely related compound, laureacetal-B (137), and it is suggested that this compound is the... 

New bisabolane sesquiterpenoids from a variety of plant sources include (95)— (102).59-64 f-y-Bisabolene-8,9-epoxide (103) has been isolated from the alga Laurencia nipponica.65 This compound is possibly the precursor of various halo-genated chamigranes which are abundant in Laurencia algae. 

Full details of an earlier synthesis of chamigrene (161) have been published.95 Further work on the components of the red alga Laurencia nipponica Yamada has resulted in the isolation and structural elucidation (by Y-ray analysis) of the diol (162)96 and spironippol (164).97 The biogenesis of the latter compound can be viewed in terms of an intramolecular cyclization of the diol (163) derivable from the naturally occurring epoxide of 10-bromo-a-chamigrene. 

The absolute stereochemistry of the C-12 and C-13 oxirane moiety of laureoxolane (157), a colorless unstable bromoether obtained from extracts of Laurencia nipponica, was determined on the basis of a chiral synthesis of 156, a degradative derivative of 157. The C-5 to C-8 unit with two asymmetric centers at C-6 and C-7 of 157 corresponds to (25, 35)-l-benzyloxy-3,4-epoxy-2-butanol (142). Elongation of 142 using butyllithium and copper cyanide followed by the creation of a new epoxide provides 152. Lithium acetylide ethylenediamine complex addition to 152 and subsequent ketalization affords the acetylenic acetonide 153, which is coupled with (2i ,35)-l,2-epoxy-3-benzoyloxypentane (154) to furnish 155. Subsequent five-step transformation of 155 provides 156 [60] (Scheme 37). 

Metab. of Laurencia nipponica. Cryst. (diisopropyl ether). 

---