Intramolecular acylation, of the

Acylation of j8-carboline under Schotten-Baumann conditions yields the ind-N-, cy derivative. An intramolecular acylation of the cis-isomer of 278 to yield 279 has been carried out (see Section V). On the other hand, intramolecular acylation at the pyr-N of a j8-carboline, in the instance of the spontaneous cyclization of 281 to the pentacyclic compound 282, has been reported. 

The indolizinoquinoline 106 can be prepared by intramolecular acylation of the precursor 105. The organolithium derivative of 105 reacts intramolecularly with the amide this Parham-type reaction gives the triheterocyclic product in reasonable yield, and higher yields are obtained when the Weinreb-type methoxyamide (Rz = OMe) is used (Equation 21) <20030L1115>. 

Me2N(CH2)mNMe2 (Fig. 16) and that for the formation of N-tosylaza-cycloalkanes [9] (Fig. 10). We have also pointed out (p. 49) that the effect of chain length on the ease of closure of [11] by intramolecular acylation of the... 

The photocycloaddition precursor ent-6 was obtained from 19 by transformation into the corresponding acid chloride and AlCl3-mediated intramolecular acylation of the double bond. While the conciseness of this strategy is appealing, drawbacks are the low yields achieved in the individual reaction steps giving ent-6 in an overall yield of only 5%. 

An early example of an intramolecular acylation of the pyrrole N-atom was provided by H. Fischer who obtained pyrrolizinone 87 from acid 86 using acetic anhydride.61 The scope of this reaction may be limited because cyclization of the acid 88 to the lactam 89 proceeds in moderate yield.23... 

This polycyclic 2-benzopyrylium salt was also obtained in good yield from the 2-benzopyrylium salt 56, through intramolecular acylation of the intermediate isochromene derivative 60. The same approach was used later by Elliott and co-workers (84CJC2435) in the synthesis of some benzofc]-phenanthridine analogs. 

Intramolecular acylations of the Friedel-Crafts type will also take place with 3-aminopyridine derivatives but usually require either stringent conditions or the presence of further activating groups in the pyridine nucleus. The report that the acid 191 can be converted into... 

The formation of lactone 167 as the major compound derived from 166 was rationalized as follows the intramolecular acylation of the sulfinyl oxygen... 

An interesting application of this protocol was utilized in the total synthesis of ( )-pumiliotoxin.82 Intramolecular acylation of the a-anion of vinyl sulfone 128 gave enaminone 129 which was readily converted to the desired alkaloid pumilio-toxin 130 (Scheme 35). 

The intramolecular acylation of the vinyl lithium derivative of 63, prepared by exchange of iodine with lithium (chapter 8) with the Weinreb amide on the side chain gives the five-membered heterocyclic ring in 64, an intermediate on the way to (-)-brunsvigine 65, an alkaloid of the montanine group.14... 

Intramolecular acylations of the Bischler-Napieralski type have been used as crucial steps in the synthesis of indole alkaloids of the yohimbine class <94JCS(Pl)299, 94TL1071>. Also, the aluminum chloride-catalysed reaction of the indolosuccinic anhydride (46) gave the bridged cyclic product (47) rather than the cyclopentanone (49), presiunably because the reaction involves initial acylation at C-3 and reaction via the less strained intermediate is favored. Formation of the cyclopentanone (49) can be achieved using the polyphosphate ester cyclodehydration of the modified intermediate (48) (Scheme 13) <90JCS(Pi)2487>. 

In a new kind of process, iV-allylskatole reacts with a nitrile and a palladium acetonitrile complex to give a palladium complex of proposed structure (51), presumably via intramolecular acylation of the nitrilium cation (50). The complex (51) can be converted into the pyrazinoindole (52) by reaction with benzylamine or the tetrahydro analog (53) with sodium borohydride (Scheme 14) <86JA6224>. Acylation has been effected at C-7 in some 4,6-dimethoxyindoles <94ti(M97>. 

The starting material is C8Hg02 so A has an extra C7H4O. This looks like the addition of PhCOCI with the loss of HCl. The most obvious reaction is acylation of the phenohc oxygen rather than enolate formation as OH is much more acidic than CH and pyridine is a weak base. This phenol is unusually acidic as the carbonyl group helps to stabilize the anion. Compound A is simply the benzoate ester of the phenol. Treatment with KOH isomerizes A to B and this is the heart of the problem. An intramolecular acylation of the only possible enolate can be catalysed by KOH even though it produces only a little enol as cychzation to form a six-membered ring is so easy. 

Acyclic carbohydrate-derived dienes have been described by Reitz, Jordan, and Maryanoff. Diene 54, derived from arabinose, underwent cycloaddition to N-phenylmaleimide to give lactone 56 in a yield of 51% 28). A minor isomeric product was also obtained in 16% yield. The major product results from an intramolecular acylation of the initial endo cycloadduct. The stereoselectivity of the addition was found to be consistent with that reported in other studies involving koxy-substituted dienes. 

Acylation of j8-carboline under Schotten-Baumann conditions yields the ind-N- cy derivative. An intramolecular acylation of the cis-isomer of 278 to yield 279 has been carried out (see Section... 

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