Ring formula index

The pyrrolopyridines contain one nitrogen heteroatom in the five-membered pyrrole ring and one nitrogen atom in the six-membered pyridine ring. A more common name is azaindoles, with 7-azaindole (l//-pyrrolo[2,3-6]pyridine (1)) being the most widely studied isomer of the series. Twelve isomers of pyrrolopyridines are listed in the Chemical Abstracts Ring Formula Index. Table 1 lists the pyrrolopyridines with their Chemical Abstracts Registry Numbers. The 1//-pyrrolopyridines (l)-(6) are the most frequently prepared, but some work has also been carried out on the isomers (7), (8), and (10). Isomers (8), (9), (11), and (12) are tautomeric structures which are considered later (see Section 7.06.4.4). 

Ring Systems File II RF 27596-RF 52845, Ring Systems File III RF 52846-RF 72861, Ring Formula Index, Ring Name Index. 

The Ring Formula Index is a list of molecular formulas of all ring systems with ring atoms quoted in alphabetical order, H-atoms being omitted, e.g. C6N4 2 RINGS, CN4-C6N, 17/-Tetrazolo[l,5-(2]azepine [RF 9225]. 

Organization and use of the Ring Systems File, Ring Formula Index and Ring Name Index are, in each case, explained in detail at the beginning of the book. 

Band 4 Ring Formula Index, Ring Name Index. ... 

RAMP 160 Reboxetin 448 Ring analysis 15 Ring-chain tautomerism (tetrazole) 275 Ring formula index 16 Ring inversion see inversion Ring name index 16 Rose furan 78 Rotenone 341... 

Fig. 74. Excerpt from the Ring Formula Index to the Ring Systems Handbook...

CAS Registry Numbers are included in the printed Chemical Abstracts chemical substance and formula indexes and in the CAS databases. The full set of CAS Chemical Registry System database information—structures, names, formulas, and ring data—is available for search and display through STN International, SciFinder, and other CAS search services. CAS Registry information is also available in CAS databases offered by other online system vendors. 

The Index of Ring Systems was discontinued after the twelfth Collective Index period. For the 1st to the 6th Collective Indexes, Ring System Information was included in the introduction to the Subject Index for the 7th to the 12th Collective Indexes, the Index of Ring Systems was bound with the Formula Index. 

Appendix II Indexes to Chemical Abstracts Organisation and Use is a comprehensive account of the organisation, and relationships, of the CA Chemical Substance Index, CA General Subject Index, CA Formula Index, and CA Index of Ring Systems. This appendix also describes the CAS Chemical Registry System and the criteria applied in selecting CA index entries. 

Chemical Abstracts (CA) consists of two main parts, abstracts of every paper containing new chemical information, and indexes which provide access to the abstracts and thence to the original literature. It is published weekly and each issue contains a keyword index and an author index. The weekly issues are collected in volumes covering a six month period (one year, prior to 1962) and each volume contains author, chemical substance, formula, general subject, patent, and ring system indexes. Every five years (ten years, prior to 1957) the indexes for the ten volumes are combined to give Collective Indexes. These indexes are the single most important and comprehensive information tool available to the chemist... 

Certain other interrelations of indexes are helpful in searching. The Ring Index aids in the use of the Subject Index, for example. Another example is the use of the Author Index to learn of possible other related work of an author when his work on some subject of interest has been discovered by use of the Subject or Formula Index. 

Tri-, tetra- to polycyclic compounds (part B) appear in the structural formula index in order of ring size (carbocyclic before heterocyclic ring compounds) under appropriate compound headings. Part C contains spiro compounds with similar ordering followed by part D which contains assemblies of identical cyclic systems (c.g., bicyclopropyl). 

The print edition of Chemical Abstracts appeared in weekly issues. Six months of these issues constituted a volume that was accompanied hy six indexes General Subject Index, Chemical Substance Index, Formula Index, Index of Ring Systems, Author Index, and Patent Index [12], January to June of 1993 was volume 118. Ten volumes (5 years coverage) were combined in the Collective Indexes, the 11th collective volumes covered the years from 1982 to 1986 and comprised 93 hound hooks occupying 17 feet of shelf space. It is easy to see why the print version is no longer published. 

The Formula Index and the Index of Ring Systems are both tools which enable the Chemical Substance Index to be used more effectively. 

There are variations in representation of rings in different disciplines. The dye industry does not designate aromaticity or double bonds in rings. AH double bonds and aromaticity are shown in the Encyclopedia as a matter of course. For example, tetralin has an aromatic ring and a saturated ring and its stmcture appears in the Encyclopedia with its common name. Registry Number enclosed in brackets, and parenthetical CA index name, ie, tetralin [119-64-2] (1,2,3,4-tetrahydronaphthalene). With names and stmctural formulas, and especiaHy with CAS Registry Numbers, the aim is to help the reader have a concise means of substance identification. 

Index of hydrogen deficiency (Section 13.23) A measure of the total double bonds and rings a molecule contains. It is determined by comparing the molecular formula C Hj. of the compound to that of an alkane that has the same number of carbons according to the equation ... 

According to the systematic nomenclature these substances were first named l-f-triazolo[d] pyrimidines in compliance with the general principles of the Ring Index/ More recent papers and Chemical Abstracts indexes use the term i -triazolo[4,5-d]pyrimidine (147) in accord with the lUPAC nomenclature. The numbering of substituents when using the last-mentioned name is different from that of the 8-aza analogs. For the formulas of oxygen and sulfur derivatives names derived from the lactim or thiolactim form are almost exclusively in use (in common with the purine derivatives). These derivatives are thus described as hydroxy and mercapto derivatives, respectively. The name 1,2,3,4,6-pentaazaindene is used only rarely for this system. 

The n-d-M correlation is an ASTM (D-3238) method that uses refractive index (n), density (d), average molecular weight (MW), and sulfur (S) to estimate the percentage of total carbon distribution in the aromatic ring structure (% C ), naphthenic ring structure (Cj,), and paraffin chains (% Cp). Both refractive index and density are either measured or estimated at 20°C (68°F). Appendix 4 shows formulas used to calculate carbon distribution. Note that the n-d-M method calculates, for example, the percent of carbon in the aromatic ring... 

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