Novel precursor synthesis

A Japanese group have been investigating the use of readily accessible dihydrocinnoline derivatives of the type 1 (R = alkyl, aryl, styryl, ethoxy X = H or methoxy) as novel precursors for the synthesis of other types of heterocycles. The following synthesis of 2-acetyl-3-cyanoindole is representative of a new general method (22-88% for 10 examples) for the preparation of 2-acyl- and 2-ethoxycarbonyl-3-cyanoindoles from 1 a mixture of 1 (R = Me, X = H 1 eq.) and powdered potassium cyanide (2 eq.) was stirred overnight in aqueous DMF at room temperature. Addition of water to the reaction mixture precipitated 2-acetyl-3-cyanoindoIe, which was obtained in 54% yield after recrystallisation. 

Pseudomonas putida oxidation of benzene affords cis-3,5-cyclohexadiene-l,2-diol which is used as a novel precursor for the synthesis of D- and L-myo-inositol trisphosphates, which was prepared in 11 steps ... 

Carbenes, as synthetic species, are fascinating chemicals, and the synthesis of cyclopropanes by a [2 +1] cycloaddition of alkenes with carbenes represents an extremely fruitful approach. Recently, highly effective intramolecular [2 + 1] cycloadditions, novel triplet sensitizers, metal-catalyzed cyclopropanations, and novel precursors of carbenes have been developed. 

Poonian, M S, Nowoswiat, E F, A novel precursor for the synthesis of C-nucleoside analogs. Synthesis of the C-nucleoside analogs of ribavirin, bredinin, and related compounds, J. Org. Chem., 45, 203-208, 1980. 

The synthetic potential of a novel precursor of 2,6-diaminopurine CDK inhibitors, 2-(benzylsulfanyl)-6-chloro-9-isopropylpurine, has been described <05EJO939>. Novel highly potent adenosine deaminase inhibitors containing the pyrazolo[3,4-c/]pyrimidine ring system have been reported <05JMC5162>. The synthesis of substituted 6-phenylpyrazolo[3,4-c/]pyrimidines as potential adenosine A(A2) receptor antagonists has been published... 

The utility of 141 was emphasized by a recent synthesis of idarubicinone (9) [146] (Scheme 30). Cycloaddition of quinone 143, prepared from 141 by ketalization and cerimn ammonimn nitrate (CAN) oxidation [20], with a novel precursor of o-quinone dimethide [146], tran -, 2-bis(trimethylsilyloxy)benzocyclobutane (142), and subsequent removal of protecting groups gave idarubicinone (9) in 65% overall yield. 

Khan N, Cheng X, Mootoo DR (1999) l-Thio-l,2-0-isopropylidene acetals novel precursors for the synthesis of complex C-glycosides. J Am Chem Soc 121 4918-4919... 

M. P. Baldus, 0. Wagner, and M. Jansen, Synthesis of advanced ceramics in the systems Sl-B-N and Si-B-N-C employing novel precursor compounds. Mater. Res. Soc. Proc., Vol. 271, The Materials Research Society, Pittsburgh, PA, 821-826 (1992). 

These novel precursors are not only easily prepared from silicon dioxide and trial-kanolamine in ethylene glycol solvent, but are also moisture stable. With this remarkable latter property, silatrane precursors have proved to be good candidates to achieve the synthesis of not only mesoporous (Thanabodeekij et al. 2006 Tanglumlert et al. 2007 Samran et al. 2011) (Figure 12.2), but also microporous materials (Sathupunya et al. 2002,2003 Phiriyawirut et al. 2003 Phonthammachai et al. 2003) (Figure 12.3). 

In studies toward the synthesis of glycyrol, Kim and coworkers employed a novel precursor, iodium acetate salt 7, which was successfully incorporated into a novel Smiles rearrangement, ultimately leading to the first total synthesis of glycyrol (Figme 18.1) [4]. 

Alikhanzadeh-Arani, S. and Salavati-Niasari, M. (2012) Synthesis and characterization of high-temperature ceramic YBCO nanostructures prepared from a novel precursor. /. Nanostruct, 1, 62-68. 

Bartole-Scott A, Braunschweig H, Kupfer T et al. (2006) Synthesis of anra-[n]silacyclo-pentadienyl-cycloheptatrienyl-chromium complexes (n = 1,2) novel precursors for polymers bearing chromium in the backbone. Chem Eur J 12 1266-1273... 

The synthesis of carcerand 5 involved the formation of two novel precursor cavitands 3 (Scheme 9.2, X = CH2CI2 and CH2SH respectively) which were subsequently joined in 29 % yield. However, the product was insoluble in all tested solvents, making purification and full characterization difficult... 

Our trusted friend Osmium has been stressing this following recipe as a breakthrough P2P synthesis for speed from a very unlikely precursor. It is apparently a novel rearrangement of a... 

A number of highly potent DHP-I stable iP-methylcarbapenems having a variety of C-2 substituents have now been described (60,66—69) including SM 7338 [96036-03-2] (42), C yH25N20 S. An acylamiao compound (66) and a iP-methoxy analogue (70) provide other variations. The pyrroHdine substituted iP-methyl-carbapenem SM 7338 (42) is being developed as a broad-spectmm parenteral antibiotic under the name meropenem the synthesis of (42) is by way of the lactone (43) derived by a novel Diels-Alder approach to dihydropyran precursors of (43) (71). 

The wide applicability of the PK reaction is apparent in the synthesis of pyrroles, for example, 45, en route to novel chiral guanidine bases, levuglandin-derived pyrrole 46, lipoxygenase inhibitor precursors such as 47, pyrrole-containing zirconium complexesand iV-aminopyrroles 48 from 1,4-dicarbonyl compounds and hydrazine derivatives. The latter study also utilized Yb(OTf)3 and acetic acid as pyrrole-forming catalysts, in addition to pyridinium p-toluenesulfonate (PPTS). 

Migrastatin (192) (Scheme 37) is a novel macrolide natural product that displays an inhibitory effect on the migration of human tumor cells. After an RCM-based synthesis of the 14-membered macrolide core of 192 [94], Danishefsky also achieved the first total synthesis of the natural compound [95], using the fully functionalized tetraene 191 as the metathesis precursor. Under the conditions shown in Scheme 37, the ring-closing step proceeded (E)-selectively with exclusive participation of the two terminal double bonds in 191, delivering only the ( , ,Z)-trienyl arrangement present in 192. 

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