title: Some structural and photochemical studies in triterpenoids

authors: Zhu, Julie Hehui

abstract: This thesis describes the photochemical behaviour of 22-hydroxyhopan-7-one, hop-22(29)-en-7-one, 22-hydroxyhopan-15-one, hop-21-en-15-one, hop-22(29)-en-15-one, hopan-15-one and 21α-H-hopan-15-one in different solvents, and the isolation and structural elucidation of a new stictane and a new flavicane triterpene from the New Zealand lichen Pseudocyphellaria colensoi.

Photolysis of 22-hydroxyhopan-7-one in benzene-methanol was reinvestigated and confirmed to afford methyl 22-hydroxy-7,8-secohopan-7-oate. The photochemical behaviour of 22-hydroxyhopan-7-one and hop-22(29)-en-7-one in the presence of benzene alone, and in benzene-isopropanol, were also investigated.

Photolysis of hop-22(29)-en-7-one in benzene-methanol afforded methyl 7,8-secohop-22(29)en-7-oate while photolysis of 22-hydroxyhopan-7-one in methanol-isopropanol afforded isopropyl 22-hydroxy-7,8-secohopan-7-oate. Photolysis of 22-hydroxy-hopan-7-one in benzene alone afforded mainly unreacted starting material and some minor products, one of which was believed to be 22-hydroxy-7,8-secohop-8(26)-en-7-al.

The stereochemistry at C-8 for these compounds was determined by analyses of ROESY or NOESY NMR spectral data which showed the C-8 methyl group to be β-oriented, and indicated that photochemical rearrangement reactions proceeded with retention of configuration at C-8. Modelling analyses indicated the 8β-methyl secoesters to have lower energy than the corresponding 8α-methyl isomers.

Complete assignments of the ¹H and ¹³C NMR signals of methyl 22-hydroxy-7,8-secohopan-7-oate, isopropyl 22-hydroxy-7,8-secohopan-7-oate and methyl 7,8-secohop-22(29)-en-7-oate, were achieved using a combination of one- and two-dimensional NMR techniques.

The three products obtained on photolysis of 22-hydroxyhopan-15-one, in benzene-methanol, benzene-isopropanol, or benzene alone, were identified as 14,15-seco-15,22-O-abeohop-14(27)-en-15α-ol, 14,15-seco-15,22-O-abeohop-14(27)-en-15-one, and 14,15-seco-15,22-O-abeohopa-14(27), 15-diene, respectively. These products can be envisaged as arising from participation of the 22-hydroxyl group in the photoreaction pathway, after the initial formation of a 14,15-secoaldehyde.

Photolysis of hop-21-en-15-one in benzene-methanol afforded 14,15-secohopa-14(27),21-dien-15-al as the major product, while photolysis of hop-22(29)-en-15-one gave a complex mixture of products which was not further investigated. Photolysis of hopan-15-one yielded two products which were identified as the isomeric alcohols, 14,15-seco-15,22-abeohop-14(27)-en-15α-ol and 14,15-seco-15,22-abeohop-14(27)-en-15β-ol. Photolysis of 21α-H-hopan-15-one afforded two products, which were identified as methyl 14α,21α-H-14,15-secohopan-15-oate and methyl 21α-H-14,15-secohopan-15-oate.

Complete assignments of the ¹H and ¹³C NMR signals of the foregoing series of 15-oxohopanoid photoreaction products, and where appropriate the stereochemistry at C-14 and/or C-15, were achieved using a combination of one- and two-dimensional ROESY, NOESY, COSY, HMBC, and HSQC NMR spectral data, and molecular modelling results.

The results of the series of 15-oxohopanoid photoreactions can be interpreted indicating that in the presence of an α-oriented side chain (ie 22-hydroxyisopropyl group or isopropyl group) at C-21, the photoreaction proceeds with hydrogen transfer via an eight-membered transition state to afford a secoaldehyde or 14,15-secohop-4(27)-en-15-al which then affords 14,15-seco-15,22-O-abeohop-14(27)-en-15α-ol via participation of the 22-hydroxyl group and related analogues. Similarly the isomeric alcohols, 14,15-seco-15,22-abeohop-14(27)-en-15α-ol and 14,15-seco-15,22-abeohop-14(27)-en-15β-ol, obtained on photolysis of hopan-15-one can be viewed as 22-H participation products. On the other hand photolysis of a 15-oxohopanoid possessing a β-oriented side chain at C-21 was found to proceed with hydrogen transfer via a six-membered transition state to afford a pair of epimeric 14,15-secoesters.

A new stictane triterpene, and a new flavicane triterpene were isolated from extracts of the New Zealand lichen Pseudocyphellaria colensoi, and identified by analyses of mass spectral and one- and two-dimensional NMR spectral data to be 3α,6β,22α-triacetoxystictane and 22-hydroxyflavicano-25,3β-lactone, respectively. Complete assignments of the ¹H ¹³C NMR signals of the new triterpenes, and revisions to previously reported ¹³C NMR signal assignments for 22α-hydroxystictano-25,3β-lactone are reported.

text: Some structural and photochemical studies in triterpenoids This thesis describes the photochemical behaviour of 22-hydroxyhopan-7-one, hop-22(29)-en-7-one, 22-hydroxyhopan-15-one, hop-21-en-15-one, hop-22(29)-en-15-one, hopan-15-one and 21α-H-hopan-15-one in different solvents, and the isolation and structural elucidation of a new stictane and a new flavicane triterpene from the New Zealand lichen Pseudocyphellaria colensoi.

Photolysis of 22-hydroxyhopan-7-one in benzene-methanol was reinvestigated and confirmed to afford methyl 22-hydroxy-7,8-secohopan-7-oate. The photochemical behaviour of 22-hydroxyhopan-7-one and hop-22(29)-en-7-one in the presence of benzene alone, and in benzene-isopropanol, were also investigated.

Photolysis of hop-22(29)-en-7-one in benzene-methanol afforded methyl 7,8-secohop-22(29)en-7-oate while photolysis of 22-hydroxyhopan-7-one in methanol-isopropanol afforded isopropyl 22-hydroxy-7,8-secohopan-7-oate. Photolysis of 22-hydroxy-hopan-7-one in benzene alone afforded mainly unreacted starting material and some minor products, one of which was believed to be 22-hydroxy-7,8-secohop-8(26)-en-7-al.

The stereochemistry at C-8 for these compounds was determined by analyses of ROESY or NOESY NMR spectral data which showed the C-8 methyl group to be β-oriented, and indicated that photochemical rearrangement reactions proceeded with retention of configuration at C-8. Modelling analyses indicated the 8β-methyl secoesters to have lower energy than the corresponding 8α-methyl isomers.

Complete assignments of the ¹H and ¹³C NMR signals of methyl 22-hydroxy-7,8-secohopan-7-oate, isopropyl 22-hydroxy-7,8-secohopan-7-oate and methyl 7,8-secohop-22(29)-en-7-oate, were achieved using a combination of one- and two-dimensional NMR techniques.

The three products obtained on photolysis of 22-hydroxyhopan-15-one, in benzene-methanol, benzene-isopropanol, or benzene alone, were identified as 14,15-seco-15,22-O-abeohop-14(27)-en-15α-ol, 14,15-seco-15,22-O-abeohop-14(27)-en-15-one, and 14,15-seco-15,22-O-abeohopa-14(27), 15-diene, respectively. These products can be envisaged as arising from participation of the 22-hydroxyl group in the photoreaction pathway, after the initial formation of a 14,15-secoaldehyde.

Photolysis of hop-21-en-15-one in benzene-methanol afforded 14,15-secohopa-14(27),21-dien-15-al as the major product, while photolysis of hop-22(29)-en-15-one gave a complex mixture of products which was not further investigated. Photolysis of hopan-15-one yielded two products which were identified as the isomeric alcohols, 14,15-seco-15,22-abeohop-14(27)-en-15α-ol and 14,15-seco-15,22-abeohop-14(27)-en-15β-ol. Photolysis of 21α-H-hopan-15-one afforded two products, which were identified as methyl 14α,21α-H-14,15-secohopan-15-oate and methyl 21α-H-14,15-secohopan-15-oate.

Complete assignments of the ¹H and ¹³C NMR signals of the foregoing series of 15-oxohopanoid photoreaction products, and where appropriate the stereochemistry at C-14 and/or C-15, were achieved using a combination of one- and two-dimensional ROESY, NOESY, COSY, HMBC, and HSQC NMR spectral data, and molecular modelling results.

The results of the series of 15-oxohopanoid photoreactions can be interpreted indicating that in the presence of an α-oriented side chain (ie 22-hydroxyisopropyl group or isopropyl group) at C-21, the photoreaction proceeds with hydrogen transfer via an eight-membered transition state to afford a secoaldehyde or 14,15-secohop-4(27)-en-15-al which then affords 14,15-seco-15,22-O-abeohop-14(27)-en-15α-ol via participation of the 22-hydroxyl group and related analogues. Similarly the isomeric alcohols, 14,15-seco-15,22-abeohop-14(27)-en-15α-ol and 14,15-seco-15,22-abeohop-14(27)-en-15β-ol, obtained on photolysis of hopan-15-one can be viewed as 22-H participation products. On the other hand photolysis of a 15-oxohopanoid possessing a β-oriented side chain at C-21 was found to proceed with hydrogen transfer via a six-membered transition state to afford a pair of epimeric 14,15-secoesters.

A new stictane triterpene, and a new flavicane triterpene were isolated from extracts of the New Zealand lichen Pseudocyphellaria colensoi, and identified by analyses of mass spectral and one- and two-dimensional NMR spectral data to be 3α,6β,22α-triacetoxystictane and 22-hydroxyflavicano-25,3β-lactone, respectively. Complete assignments of the ¹H ¹³C NMR signals of the new triterpenes, and revisions to previously reported ¹³C NMR signal assignments for 22α-hydroxystictano-25,3β-lactone are reported.

year: 2000

title: Stories from the inside: A narrative analysis investigating the professional lives of three New Zealand secondary school heads of English departments

authors: Wright, Noeline

subjects: Head of department

abstract: This research is a narrative analysis based on an investigation into the professional lives of heads of English departments (HODs) in three New Zealand secondary schools. The main data collection methods of interviews and observations used in this study, fall within an interpretive paradigm.
The research breaks through prevailing silences about the realities of three HODs' professional lives. I propose that while these HODs play a pivotal role in secondary schools, their ability to engage in not only effective curriculum and pedagogical leadership but also effective classroom teaching, is seriously constrained. These constraints have occurred partly as a result of the accumulating effects of over a decade of continual educational reforms in New Zealand, partly because there have been Jew changes to staffing ratios to accommodate intensified workloads, and partly because secondary schools' basic timetable structures have not been able to change sufficiently to reflect other changes. Because consequences of the reforms on the work of these HODs have been largely ignored, I also contend that effective teaching and learning, which is the core focus of schools, is compromised.
Emotions and relationships, coupled with the effects of time constraints and complexity, are highlighted as major concerns and significant hindrances to the three HODs' work. In order to demonstrate the impact of such effects, a fictionalised short story 'from the inside' makes the personal political, exposing some of the human costs to HODs' professional lives.
This fictional story is from the inside' for at least two important reasons: the data from participants plus my own prior knowledge and experiences as an HOD. The effect of this on the research is also discussed.
Essentially, the circumstances in which the three participant English H0Ds work, may be symptomatic of an educational crisis that requires urgent attention, particularly in relation to the amount of time available for HODs to carry out their leadership roles. This research may be one step towards promoting that attention.

text: Stories from the inside: A narrative analysis investigating the professional lives of three New Zealand secondary school heads of English departments This research is a narrative analysis based on an investigation into the professional lives of heads of English departments (HODs) in three New Zealand secondary schools. The main data collection methods of interviews and observations used in this study, fall within an interpretive paradigm.
The research breaks through prevailing silences about the realities of three HODs' professional lives. I propose that while these HODs play a pivotal role in secondary schools, their ability to engage in not only effective curriculum and pedagogical leadership but also effective classroom teaching, is seriously constrained. These constraints have occurred partly as a result of the accumulating effects of over a decade of continual educational reforms in New Zealand, partly because there have been Jew changes to staffing ratios to accommodate intensified workloads, and partly because secondary schools' basic timetable structures have not been able to change sufficiently to reflect other changes. Because consequences of the reforms on the work of these HODs have been largely ignored, I also contend that effective teaching and learning, which is the core focus of schools, is compromised.
Emotions and relationships, coupled with the effects of time constraints and complexity, are highlighted as major concerns and significant hindrances to the three HODs' work. In order to demonstrate the impact of such effects, a fictionalised short story 'from the inside' makes the personal political, exposing some of the human costs to HODs' professional lives.
This fictional story is from the inside' for at least two important reasons: the data from participants plus my own prior knowledge and experiences as an HOD. The effect of this on the research is also discussed.
Essentially, the circumstances in which the three participant English H0Ds work, may be symptomatic of an educational crisis that requires urgent attention, particularly in relation to the amount of time available for HODs to carry out their leadership roles. This research may be one step towards promoting that attention.

year: 2002

title: Whiti te rā: A guide to connecting Māori to traditional wellbeing pathways.

authors: McLachlan, Andre David

abstract: Māori health models, introduced in the 1980s, brought needed cultural worldviews to an otherwise monocultural health system. However, minimal changes have occurred. In mainstream practice, deeper cultural understandings and action-orientations of these models can be overlooked, to the detriment of Māori wellbeing.
In particular, Māori cultural concepts such as mauri ora (an active state of wellbeing) and a secure cultural identity are notable core wellbeing pathways that need further exploration. Using a systematic narrative literature review, 36 papers identified pathways that used core cultural activities for Māori wellbeing. A thematic analysis produced six themes or pathways towards wellbeing for Māori – te reo Māori: Māori language, taiao: connection with the environment, wairua: Māori spiritual beliefs and practices, mahi-a-toi:
Māori expressive art forms, take pū whānau: Māori relational values, and whakapapa: intergenerational relationships. Forty experienced Māori psychologists analysed the themes and offered expert examples practice pathways for Māori wellbeing. The six themes and feedback is presented in a visual image Whiti Te Rā with instructions for Māori practitioners to guide whai ora Māori (Māori clients) to explore their level of knowledge and comfort, and active engagement with Māori pathways to wellbeing. The model has potential for mental health policy, future research, curriculum development, and synthesising Māori knowledge towards wellbeing pathways.

text: Whiti te rā: A guide to connecting Māori to traditional wellbeing pathways. Māori health models, introduced in the 1980s, brought needed cultural worldviews to an otherwise monocultural health system. However, minimal changes have occurred. In mainstream practice, deeper cultural understandings and action-orientations of these models can be overlooked, to the detriment of Māori wellbeing.
In particular, Māori cultural concepts such as mauri ora (an active state of wellbeing) and a secure cultural identity are notable core wellbeing pathways that need further exploration. Using a systematic narrative literature review, 36 papers identified pathways that used core cultural activities for Māori wellbeing. A thematic analysis produced six themes or pathways towards wellbeing for Māori – te reo Māori: Māori language, taiao: connection with the environment, wairua: Māori spiritual beliefs and practices, mahi-a-toi:
Māori expressive art forms, take pū whānau: Māori relational values, and whakapapa: intergenerational relationships. Forty experienced Māori psychologists analysed the themes and offered expert examples practice pathways for Māori wellbeing. The six themes and feedback is presented in a visual image Whiti Te Rā with instructions for Māori practitioners to guide whai ora Māori (Māori clients) to explore their level of knowledge and comfort, and active engagement with Māori pathways to wellbeing. The model has potential for mental health policy, future research, curriculum development, and synthesising Māori knowledge towards wellbeing pathways.

year: 2021