Annulated derivatives

Unusual annulated derivatives of pyrrole, 90 and 91, were found as efficient catalysts for the polymerization of propene (98JA10786). 

No monocyclic 1,2-oxazepines have been reported, but annulated derivatives are known. 

Thiazepines have not been reported (for annulated derivatives see Section 4.1.2.3., p335ff) other monocyclic thiazepines are rare.46... 

Reaction of 1,4-diazocinediones with methylating agents leads to different products depending on the conditions. With dimethyl sulfate, the annulated derivative 6 gives JV-methylation selectively 7 however, on reaction with diazomethane, a mixture of the O- and iV-methylated products is obtained.9... 

Besides the parent system oxonin (l),5,6 which is thermally unstable and undergoes a valence isomerization to 3a,7a-dihydrobenzofuran (2) above 35 C, some annulated derivatives are known. All reported systems are nonaromatic and exist in nonplanar conformations. 

Parlar, H. Angerhofer, D. Dioxins and annulated derivatives, in Houben-Weyl, Vol. E, Hetarenes IV, Thieme, Stuttgart, 1997. 

The discovery of alkylidenecycloproparenes as a class of isolable compounds is the most significant event in recent cycloproparene chemistry. Methylidenecyclo-propabenzene (234) combines the structural features of benzocyclopropene (1), methylenecyclopropene (233), and trimethylenecyclopropane (235) in one and the same structure. Although the parent 234 has so far not been isolated, many substituted and annulated derivatives have been synthesized and charaeterized. Their unexpected stability contrasts sharply with that of the benzocyclopropenones 219, which are only observable as transient reaction intermediates. Reviews on the chemistry of alkylidenecycloproparenes are available. ... 

Dioxins, 1,4-oxathiins, 1,4-dithiins, and annulated derivatives have been reviewed in 1997 <1997HOU(9a)l> More recently, synthetic methods for preparing 1,4-dioxins and their benzo- and dibenzofused derivatives <2004808(16)15, 20048L2449>, 1,4-dithiins <2004SOS(16)57> and 1,4-oxathiins, and their annulated analogs... 

A closely similar pattern of behavior is also found for the corresponding benzo-annulated derivatives. Thus, 3-hydroxybenzofuran (66CB3076) and 3-hydroxyindoles (58JCS1217) adopt the oxo form (91), but enolize to (90) when an acetyl group is present at position 2 (65T3331,60JA1187). 

The above general approach to the synthesis of various thienopyridines (1992S528, 1997S949, 1998S1095), including [2,3-c]-annulated derivatives, deserves more attention. The method is based on the reaction of halopyridines 219 with CS2 or PhNCS. Unfortunately, the yields of the target products 220 and 221 are low due, evidently, to low mobility of the bromine atom at position 3 of the pyridine ring. 

Phosphonoacrolein, (Et0)2P(0)C(CH0)=CH2, takes part in hDA reactions with alkenes and cyclic conjugated dienes, to give phosphono-substituted 3,4-dihydro-2W-pyrans and their annulated derivatives. The reaction with alkynes gives the 1 1 adduct, a 4//-pyran, initially but this undergoes a second cycloaddition leading to a tetrahydropyrano[3,2-6]pyran 3... 

The anion derived from furobenzopyrandione 28 reacts with Michael acceptors regiospecifically to yield xanthones and various annulated derivatives <03OL3753> and intramolecular trapping of the anion by a carbamate side-chain leads to spiro- pyrrolidine and piperidine 9-xanthene derivatives <03TL9291>. 

The stereoelectronic preference of sp2 centers in cyclohexane systems for axial attack128 is most probably also found in the peracid epoxidation of methylenecyclohexanes44, where selectivity for axial attack is 0.3 -0.6 keal/mol higher than predicted by the MM2 simulation throughout78. The effect is also detected in derivatives that are substituted in the methylene position, such as isopropylidene derivative 644, and even in annulated derivatives such as 7130 and 5-cholestene81 (see also Tables 3 and 4, Section 4.5.1.1.1.) or the corresponding bicyclic analogs132. 

One-pot syntheses of annulated derivatives of furan, pyrrole, pyridine, pyrane, and thiophene based on reactions of quinones with enamines 04YGK811. 

In the rearrangement of the benzo-annulated derivative 44, it has been shown that treatment with potassium hydride at 24 °C leads rapidly to an equilibrium of alcohols 44 and 46, which on prolonged reaction times rearrange to give 45 U83. 

This chapter will focus on some recent developments in the synthesis of polyacetylene itself, (CH) , and of substituted derivatives, (CR) f(CH) [24, 25]. While the great variety of other conductive polymers, including poly(phenylene vinylenes), polythiophenes and polypyrroles, may be thought of as annulated derivatives of polyacetylene [26-28], (Fig. 10-4), their syntheses and properties differ enough to put them outside the scope of this chapter. The reader is referred to a number of reviews covering both these polymers and polyacetylene [15,17, 29]. 

The 3-alkyl-3,4-dihydro-2//-l-thia-2,4-diazine 1,1-dioxide 224 is produced by heating the appropriate aldehyde with 2-aminobenzenesulfonamide in iV-methyl-2-pyrrolidone (NMP) at 100°C <2001BML3103>. 3-Aryl-3,4-dihy-dro-2//-l-thia-2,4-diazine 1,1-dioxides 225 are the products of heating preformed bis(sulfonamides) with aryl aldehydes in dimethyl sulfoxide (DMSO) <20040JC373>. The 3,4-annulated derivative 226 is the result of a reaction between the corresponding 2-aminobenzenesulfonamide and homophthalaldehyde <1996AP51>. 

Electrocyclic ring opening of oxiranes - either thermally or photochemically - yields carbonyl ylides, which can be trapped with alkynes to give dihydrofurans. If l-buten-3-ynyl-oxirans are used as starting materials, the corresponding ethenylfurans are obtained (Equation (49)). This sequence, which has been studied quite intensively by Eberbach and co-workers, can also be used to prepare annulated derivatives <93CB975>. 

Gold-containing all-carbon 1,3-dipoles, such as 203, are prepared in situ by the treatment of ketals and acetals with Ph3PAuNTf2 (5 mol%), and undergo [3-h2] cycloadditions with A-benzylindole (204) at room temperature. In the case of 202, the cycloaddition led to the formation of the cyclopentyl-annulated derivative 205 with good diastereoselectivity (55% yield) [88] (Scheme 56). 

Synthetic approaches to pyrrolo-, furo-, thienoquinolines, and their benzo or heterocyclic annulated derivatives 05H(65)901. 

Polyaza cavity terpyridines 257 were prepared from diketones 256 and 246 (Scheme 53). Similarly these diketones with o-aminobenzaldehyde afford bis-annulated derivatives of 2,6-di(2 -quinolyl)p)oidine while condensation with 2-aminonicotinaldehyde affords bis-annulated derivatives of 2,6-di(l, 8 -naphthyrid-2 -yl)pyridine (85JOC2407). 

---