ABSTRACT
Addition of ethenyllithium reagents to the carbonyl group of dialkyl squarate-derived 1-alkynylbicyclo[3.2.0]hept-2-ene-7-ones (15), followed by a TBAF workup, results in a low-temperature anion-accelerated alkoxy-Cope rearrangement which proceeds by way of a strained cyclic allene intermediates (e.g.,17). This leads to the formation of angularly fused triquinanes (e.g., 20) in which each of the rings is functionally differentiated. Bicyclo[6.3. 0]undecadienones (e.g., 36) are the major products when the reactions are quenched with aqueous bicarbonate rather than TBAF. Under analogous conditions 2-alkylidene-1-alkynylbicyclo[3.2. 0]heptan-7-ones also give bicyclo[6.3.0]undecadienones by a mechanism that was established to involve a 1,5-hydrgen shift in a strained allene intermediate. The synthetic scope and mechanism of these and related transformations are discussed.
Subject(s)
Bridged Bicyclo Compounds/chemical synthesis , Bridged Bicyclo Compounds/chemistry , Crystallography, X-Ray , Magnetic Resonance Spectroscopy , Mass Spectrometry , Molecular StructureABSTRACT
6-exo-Methylbicyclo[3.2.0]hepten-7-ones and their 2-alkylidene analogues are readily prepared from dialkyl squarates. These compounds undergo facial oxy-Cope ring expansions upon treatment with vinyllithium; the former leads to bicyclo[4.2. 1]non-1(4)-en-6-ones and the latter to the first examples of bicyclo[5.2.1]dec-1(10)-en-5-ones, compounds having exceptionally strained bridgehead double bonds. The transformations are controlled by the 6-exo-methyl group in the starting material along with the substituent at position-1 (bridgehead) which force attack of the lithium reagent from the concave face of the starting material, thus allowing the cyclopentenyl or alkylidene groups to participate in the sigmatropic event.
Subject(s)
Bridged Bicyclo Compounds/chemical synthesis , Ketones/chemical synthesis , Indicators and Reagents , Magnetic Resonance Spectroscopy , Organosilicon Compounds/chemistryABSTRACT
The Rare and Expensive Case Management Program provides intensive case management services to an especially vulnerable population comprised of primarily pediatric beneficiaries. This study examines the effect of the case management program on the pattern of costs. With its emphasis on obviating the need for acute care services and providing the necessary medical and assistive services in a timely manner, the case management program is expected to change the pattern of expenditures by category of service. Due to the low prevalence of conditions covered by the program, constituting a comparison group for the evaluation posed a major challenge. Employing an innovative methodological approach, a historical comparison group was modeled using statewide Medical Assistance claims files. The study design included a retrospective comparison of Medicaid beneficiaries enrolled in the program with a similar group before the case management program was implemented. The results bear out the anticipated pattern of shifts in cost of care from acute care to nonacute care services.
Subject(s)
Case Management/organization & administration , Disabled Children , Medicaid/organization & administration , State Health Plans/organization & administration , Case Management/economics , Child , Female , Health Care Costs , Health Services Research , Humans , Linear Models , Male , Maryland , Program Evaluation , United StatesABSTRACT
[formula: see text] This paper describes a new tandem reaction sequence leading to angularly fused polyquinanes from squaric acid-derived bicyclo[6.3.0]-undecadienediones. Such compounds undergo a dual Michael addition. The enolate form in the first intermolecular addition undergoes the second intramolecular transannular addition to give the angular polyquinanes. A particularly interesting example is a catalytic transformation of cis-13-methylyricyclo[10.3.0.0]pentadeca-4(5),12(13)-diene-3 ,14-dione to (3R*,3aS*,5aR*,9aR*,11aR*)-3-methyl-1,2,3,5,5a,6 ,7,10,11,11a-decahydro-4H- pentaleno[6a,1-c]indene-2,10-dione, a compound having the tetracyclic ring system found in the natural product waihoensene. The mechanism and synthetic scope of these reactions are discussed.
Subject(s)
Indenes/chemical synthesis , Models, Molecular , Molecular Conformation , X-Ray DiffractionABSTRACT
The material presented reveals a unique solution to meeting the health care needs of a certain population. The State of Maryland through the Maryland Medicaid High Cost User Initiative uses nursing case management to decrease costs while providing quality care. The Center for Health Program Development and Management (CHPDM) manages the program and will be providing "enhanced" case management services to the identified high-cost users under the age of 65.
Subject(s)
Case Management/organization & administration , Medicaid , Models, Nursing , Cost Control , Health Services Needs and Demand , Humans , Maryland , United StatesABSTRACT
The concept of the mode of biological action of quinones as bioreductive alkylating agents is presented. The focus of this discussion is primarily upon the structural features which would facilitate quinonemethide formation (alkylating agent) from the reduced quinone (hydroquinone). A survey of the naturally occurring quinone field was carried out and those members which can be catalogued as potential bioreductive alkylating agents are listed.
