Analog synthesizers

Ribavirin is a guanosine analog synthesized more than 35 years ago, which possesses broad-spectrum antiviral activity against several RNA and DNA viruses in vitro (Sidwell et al. 1972). When administered as monotherapy in patients with chronic hepatitis C, ribavirin induces a decline of serum alanine aminotransferase (ALT) levels while no effect on sustained virologic response is detectable (Di Bisceglie et al. 1992). 

For analogous syntheses of jS-enamino esters or o-aminophenyl esters see references [114] and [115], respectively. 

Compound 56 is the first branch point intermediate in the analog syntheses, furnishing 90 upon oxidative cyclization with MnC>2 and deprotection with Mgl2. Intermediate 56 was also benzylated to protect the C5,C5 -naphthols in preparation for ester hydrolysis, which provided the next key branch point intermediate, bisacid 91. Ester hydrolysis here with aqueous base was surprising facile relative to intermediate 62, en route to (+)-calphostin D (Scheme 7.14). Presumably, the smaller C7,C7 -groups alleviate the steric gearing that hinders the reactivity of the C3,C3 -esters. 

Table 1. Selected epothilone intermediates and analogs synthesized via ringclosing metathesis... 

Groger H (2003) Catalytic enantioselective Strecker reactions and analogous syntheses. Chem Rev 103(8) 2795-2827... 

Scheme 8.18 Nonylprodigiosin analogs synthesized by RCM and self-metathesis with catalyst IX.

Finally, we have reported the analogous syntheses of Cp Cr(0)Cl2 and CpCr(0)Cl2 via reaction of the corresponding cyclopentadienyl chrom-ium(III) chlorides with O2 (Eq. 11) [26]. While these reactions are slow (days at room temperature) they produce the 0x0 complexes in high yield. 

Mit N-Benzyliden-glycin-ethylester wird fur (R)-Phenylalanin eine analoge Synthese mit 89,9 % e. e. be-schrieben Jintai Chen, Yaohnan Chen u. Huaiyu Sheng, Youji Huaxne 8, 164(1988) C. A. 110. 24259 (19889). 

Reports in the early 1980s of a rapidly progressive form of parkinsonism in young persons opened a new area of research in the etiology and treatment of parkinsonism. The initial report described apparently healthy young people who attempted to support their opioid habit with a meperidine analog synthesized by an amateur chemist. 

Anthraquinones. A regioselective synthesis of polyhydroxyanthraquinones is based on Dicls-Alder reactions of I with chloro-substituted naphthoquinones. An example is the synthesis of 1,6-dihydroxyanthraquinone (3) from 3-chlorojuglone (2). Analogous syntheses arc possible by use of vinylogous kctcnc acetals related to I. 

Analogs synthesized from the total synthetic manifold. 

The analogs synthesized by Che et al. (Bayer AG) are reported to be in the preclinical stage directed towards the development of new analgesics (Pharmaprojects No. 

In analogous syntheses, the anionic metal carbene precursor [(ju-C5H5)(CO)2W(jm-CHR)W(CO)s] gives (118), and using carbyne complexes the derivatives (119) and (120) can be built up in a stepwise manner (R = 4-tolyl).749,750... 

For analogous syntheses of amides and sulfonamides, see also page 1628, Section 3. For alkyne — enamine, see also page 418, Section 2.4. 

One of the earliest machines for audio manipulation was GROOVE, an experimental machine built at Bell Laboratories [Mathews and Moore, 1970], GROOVE was composed of a digital computer controlling an analog synthesizer. The emphasis was on the human interaction, not the analysis or synthesis of sound. 

Analogous syntheses of 9-phosphaanthracenes have been accomplished 8,21,22>. However, attempted extension to 9-stibaanthracene 11 was less satisfactory. On treatment of 9-chloro-9,10-dihydrostibaanthracene 12 with base, the stibaanthracene could not be detected spectroscopically. However, the isolation of the dimer 13 of stibaanthracene is consistent with its intermediacy 19). 

Many examples of electrochemically prepared anionic complexes are known [202,506,507,551]. Among them, the coordination compounds with ammonium cations are of interest [506,507]. In these syntheses, it is possible to vary the composition of complexes of the type [(R4N)mMX ]. Thus, similar complexes (R = Me, X = SCN, m = 2, 3, 4 m = 4, 6) were obtained by dissolution of metals (Mn, Fe, Co, Cu, Zn, Cd) in aqueous medium, containing (Me4N)SCN [561], Analogous syntheses with use of pyridine, 2,2 -bipy, and 1,10-phen (L) lead to neutral complexes, for instance (3.241) [561] ... 

Tokunaga, f. Ebrey, T. Crouch, R. (1981) Purple membrane analogs synthesized from C17 aldehyde. Photoehem. Photobiol vol 33, pp 495-499 230Zingoni, et. al. (1986) Op. Cit. 

M. M. Joullie, T. R. Thompson, Ninhydrin and Ninhydrin Analogs. Syntheses and Applications, Tetrahedron 1991, 47, 8791-8830. 

H. Groeger, Catalytic Enantioselective Strecker Reactions and Analogous Syntheses, Chem. Rev. 2003, 103, 2795-2827. 

Dibenzoyl-2,5,6-triphenylpyridine (27) with benzylamine gave a mixture of hexaphenyl-2,7-naphthyridine (28) and the 2,6-isomer (KOH, EtOH, reflux 35% and 25%, respectively, after separation) also analogous syntheses.1132... 

The [D-Ser2]- and [Pro2]-neo-kyotorphin analogs synthesized by Kitagawa et al.57) are 10 times as active as native neo-kyotorphin. 

The Traube synthesis still remains valuable as a route to the synthesis of specific purines. The method has been used to record the first synthesis of hypoxanthine-/V(7)-oxide (30) by reaction of 6-chloro-5-nitro-4(3H)-pyrimidinone with A-(4-methoxybenzyl)phenacylamine (Scheme 18) <92CPB612>. The same authors also report analogous syntheses of 8-methylguanine-7-oxide and its 9-arylmethyl derivatives, and guanine-7-oxide and some 9-substituted derivatives (92CPB343, 92CPB1315). 

Alkoxy-l-boronobutadiene reacted with maleimides, acrylates, and acrylamides to provide cyclic allyl boronates which undergo allylboration with aldehydes (Equation (148)).409 Analogous syntheses of cyclic allylboron compounds via [2+4]-cycloaddition is discussed in Section 9.05.2.2.1. 

Analogous syntheses of rhenium, ruthenium and rhodium complexes are also described in Ref. [66],... 

The second family of superconducting materials is based on cation-radical salts of another donor, bis(ethylenedithio)-TTF (abbreviated BEDT-TTF or ET), which exhibit two-dimensional network mostly due to inter-stack S S interactions [100]. Another important feature of BEDT-TTF salts is their tendency to give polymorphs. For instance, (BEDT-TTF)2I3 salt affords four polymorphs (a, p, 0, and k phases), of which only the first undergoes metal-insulator transition, while the others are superconductors at ambient pressure (see Chapter 10 of this book). It is quite surprising that of all numerous BEDT-TTF structural analogs synthesized to date, only two salts of unsymmetrical derivatives, DMET [101] and MDT-TTF [102], led to superconductors. 

Oxadiazolc derivatives (sydnonimines) 328 and oxazolcs 329 (Fig. 126) can be synthesized from Mannich bases of hydrogen cyanide po.s.scssing a secondary amino group, as ring closure may take place by condensation with nitrous acid " or anhydride, respectively. Analogous. syntheses of spiroidantoins arc reported. ... 

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