|
|
[
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{
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"name": "IChO-2025_1",
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"background": {
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"image": "images/1/1_bg.png",
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"context": "Sesquiterpenes have the formula C_{15}H_{24}. They are secondary metabolites in plants and both deter insects which eat plants and attract animals which eat the insects. Isocaryophyllene (i-Cy) is a sesquiterpene found in oregano, rosemary, pepper, and cloves. The structural formula of i-Cy can be determined by performing various reactions and analysing the products as shown in the figure."
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},
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"points": 34
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},
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{
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"name": "IChO-2025_1.1",
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"modality": "image + text",
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"type": "Structure Construction",
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"evaluation": "Structure Match",
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"requirement": "",
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"points": 7,
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"field": "",
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"source": "IChO-2025",
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"question": {
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"context": "Draw the structures of i-Cy, A, and B.",
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"image": "images/1/1.1_ques.png",
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"requirement": "Convert the drawn structures to SMILES format (stereochemistry not required).",
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"parsing_note": "The reaction diagram has been converted to reaction_scheme.",
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"reaction_scheme": [
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{
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"reactant_name": "i-Cy",
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"reactant_formula": "C_{15}H_{24}",
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"conditions": "H_{2}, Pd/C",
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"product_name": "B",
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"product_formula": "C_{15}H_{28}"
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},
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{
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"reactant_name": "i-Cy",
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"reactant_formula": "C_{15}H_{24}",
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"conditions": "(1) BH_{3}/THF (1/3 equiv.), THF ; (2) H_{2}O_{2}, NaOH, H_{2}O",
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"product_name": "A",
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"product_formula": "C_{15}H_{26}O"
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},
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{
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"reactant_name": "i-Cy",
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"reactant_formula": "C_{15}H_{24}",
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"conditions": "(1) O_{3}, CH_{2}Cl_{2}; (2) Zn, CH_{3}COOH",
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"product_smiles": [
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"C=O",
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"CC1([C@]([H])(CCC(C)=O)[C@@](C(CCC([H])=O)=O)(C1)[H])C"
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]
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},
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{
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"reactant_name": "A",
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"reactant_formula": "C_{15}H_{26}O",
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"conditions": "(1) O_{3}, CH_{2}Cl_{2}; (2) Zn, CH_{3}COOH",
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"product_name": "C",
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"product_smiles": "CC1(C)[C@]([C@@]([H])([C@](CO)(CCC([H])=O)[H])C1)([H])CCC(C)=O"
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}
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]
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},
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"answer": [
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{
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"name": "A",
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"image": "images/1/1.1_ans_A.png",
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"smiles": "CC1=CCC[C@@H](CO)[C@]2([H])[C@]([H])(C(C)(C)C2)CC1",
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"alternative_smiles": "CC1=CCCC(CO)C2([H])C([H])(C(C)(C)C2)CC1",
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"points": 2,
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"grading": {
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"partial_credit": [
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{
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"condition": "if missing a carbon atom in the ring or added another carbon atom in the ring.",
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"deduction": -1
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}
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],
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"notes": "Stereochemistry will not be marked for A."
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}
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},
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{
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"name": "B",
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"image": "images/1/1.1_ans_B.png",
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"smiles": "CC1CC[C@@]([H])(C(C)(C)C2)[C@@]2([H])C(C)CCC1",
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"alternative_smiles": "CC1CCC([H])(C(C)(C)C2)C2([H])C(C)CCC1",
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"points": 2,
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|
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"grading": {
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"partial_credit": [
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{
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"condition": "If the structure is incorrect, but consistent with isocaryophyllene (and 2 equivalents of $H_2$ are added).",
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"deduction": 0
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}
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],
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"notes": "Also 2 pt Stereochemistry will not be marked for B."
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}
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},
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{
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"name": "i-Cy",
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"image": "images/1/1.1_ans_i-Cy.png",
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"smiles": "C/C(CC[C@]1([H])[C@]2([H])CC1(C)C)=C/CCC2=C",
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"alternative_smiles": "C/C(CCC1([H])C2([H])CC1(C)C)=C/CCC2=C",
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"points": 3,
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|
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"grading": {
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|
"partial_credit": [
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{
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|
|
"condition": "If missing a carbon atom or added another carbon atom in the ring.",
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"deduction": -1
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},
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{
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"condition": "If a ring is made by combining two other C atoms and added a methyl to the other carbon",
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"deduction": -1
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},
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{
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"condition": "If no second ring is present; only added CH3 to all/one/two carbonyls in the right-hand structure.",
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"deduction": -2
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}
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],
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"notes": "The trans-isomer gets full marks. Stereochemistry will not be marked for i-Cy."
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}
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}
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]
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},
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{
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"name": "IChO-2025_1.2",
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"modality": "image + text",
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"type": "Qualitative Identification",
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"evaluation": "Selection Check",
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"points": 3,
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|
"field": "",
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"source": "IChO-2025",
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"question": {
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"context": "Circle the stereocentres in compound C and assign them as R or S.",
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"image": "images/1/1.2_ques.png",
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"parsing_note": "The structure in the image has been converted to SMILES format.",
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"smiles": "[H][C@@]1(C(C)(C)C[C@]1([H])[C@@](CCC([H])=O)(CO)[H])CCC(C)=O",
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"requirement": "1) Count only carbon atoms (C) in the SMILES string from left to right, ignoring all other atoms like H, O, N. Number each carbon sequentially as C-1, C-2, C-3, etc. 2) Assign R or S configuration to each. Output format: 'C-X: R/S'."
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},
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"answer": {
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"context": "C-1: R, C-6: S, C-7: R",
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"image": "images/1/1.2_ans.png",
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"grading": {
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|
"partial_credit": [
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{
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"condition": "Each centre not correctly circled",
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"deduction": -1
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|
},
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|
{
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|
"condition": "Each descriptor not correct",
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"deduction": -0.5
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|
|
},
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{
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|
"condition": "Each incorrect centre is circled.",
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"deduction": -1
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|
|
}
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|
|
],
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|
|
"notes": "Minimum score is 0"
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|
|
},
|
|
|
"points": 3
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|
|
}
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|
|
},
|
|
|
{
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|
|
"name": "IChO-2025_1.3",
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|
|
"modality": "image + text",
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|
|
"type": "Structure Construction",
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|
|
"evaluation": "Structure Match",
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|
|
"points": 6,
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|
|
"field": "",
|
|
|
"source": "IChO-2025",
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|
|
"question": {
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|
|
"context": "Clovene (Cv) can be synthesised from i-Cy under acid catalysis. The synthesis of Cv starts from compound D. Draw the structures of compounds E and F.",
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|
|
"image": "images/1/1.3_ques.png",
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|
|
"parsing_note": "The reaction diagram has been converted to reaction_scheme.",
|
|
|
"requirement": "Convert the drawn structures to SMILES format (stereochemistry not required).",
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|
"reaction_scheme": [
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|
{
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|
"reactant_name": "D",
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"reactant_smiles": "C[C@@]1(CCC2)C=CC(O)[C@@]2(CC(OC)=O)C1",
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"conditions": "H^{+} (cat.)",
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"product_name": "E",
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"product_formula": "C_{12}H_{16}O_{2}"
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},
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{
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"reactant_name": "E",
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"reactant_formula": "C_{12}H_{16}O_{2}",
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"conditions": "1) LiAlH_{4}, Et_{2}O; 2) H^{+}, H_{2}O",
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"product_name": "F"
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},
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{
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"reactant_name": "F",
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"step_name": "1",
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"product_name": "G",
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|
"product_smiles": "C[C@]1(C=C2)CCC[C@](CCO)(C1)C2=O"
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|
|
},
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|
{
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|
|
"reactant_name": "G",
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|
"reactant_smiles": "C[C@]1(C=C2)CCC[C@](CCO)(C1)C2=O",
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|
"step_name": "2",
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|
"product_name": "H",
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|
|
"product_smiles": "C[C@]1(C=C2)CCC[C@](CC(O)=O)(C1)C2=O"
|
|
|
}
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|
|
]
|
|
|
},
|
|
|
"answer": [
|
|
|
{
|
|
|
"name": "E",
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|
|
"image": "images/1/1.3_ans_E.png",
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|
"smiles": "O=C1C[C@@]23C[C@@](CCC3)(C)C=C[C@H]2O1",
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|
|
"alternative_smiles": "O=C1CC23CC(CCC3)(C)C=CC2O1",
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|
|
"points": 3,
|
|
|
"grading": {
|
|
|
"partial_credit": [
|
|
|
{
|
|
|
"condition": "If the structure is not cyclic and only the ester is removed.",
|
|
|
"deduction": -2
|
|
|
}
|
|
|
],
|
|
|
"notes": "Stereochemistry will not be marked."
|
|
|
}
|
|
|
},
|
|
|
{
|
|
|
"name": "F",
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|
|
"image": "images/1/1.3_ans_F.png",
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|
|
"smiles": "O[C@H]1[C@@]2(CCO)C[C@@](CCC2)(C)C=C1",
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|
|
"alternative_smiles": "OC1C2(CCO)CC(CCC2)(C)C=C1",
|
|
|
"points": 3,
|
|
|
"grading": {
|
|
|
"partial_credit": [
|
|
|
{
|
|
|
"condition": "If reducing the ester to an aldehyde (and alcohol).",
|
|
|
"deduction": -2
|
|
|
}
|
|
|
],
|
|
|
"notes": "Stereochemistry will not be marked."
|
|
|
}
|
|
|
}
|
|
|
]
|
|
|
},
|
|
|
{
|
|
|
"name": "IChO-2025_1.4-5",
|
|
|
"modality": "image + text",
|
|
|
"type": "Qualitative Identification",
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|
|
"evaluation": "Selection Check",
|
|
|
"points": 2,
|
|
|
"field": "",
|
|
|
"source": "IChO-2025",
|
|
|
"question": {
|
|
|
"context": "Clovene (Cv) can be synthesised from i-Cy under acid catalysis. The synthesis of Cv starts from compound D. For steps '1' and '2' several reagents could be considered. For example: A. PCC B. K_{2}Cr_{2}O_{7}, H_{2}SO_{4}, H_{2}O C. MnO_{2} D. (i) OsO_{4} , (ii) KHSO_{3} From the reagents above, tick which one(s) would be suitable for step '1'. From the reagents above, tick which one(s) would be suitable for step '2'.",
|
|
|
"image": "images/1/1.4-5_ques.png",
|
|
|
"parsing_note": "The structure in the image has been converted to SMILES format.",
|
|
|
"smiles": {
|
|
|
"name": "PCC",
|
|
|
"components": [
|
|
|
"c1cc[nH+]cc1",
|
|
|
"[O-][Cr](Cl)(=O)=O"
|
|
|
]
|
|
|
},
|
|
|
"requirement": "Convert the drawn structures to SMILES format (stereochemistry not required)."
|
|
|
},
|
|
|
"answer": [
|
|
|
{
|
|
|
"name": "step 1",
|
|
|
"choice": "C",
|
|
|
"points": 1
|
|
|
},
|
|
|
{
|
|
|
"name": "step 2",
|
|
|
"choice": "B",
|
|
|
"points": 1
|
|
|
}
|
|
|
]
|
|
|
},
|
|
|
{
|
|
|
"name": "IChO-2025_1.6",
|
|
|
"modality": "image + text",
|
|
|
"type": "Structure Construction",
|
|
|
"evaluation": "Structure Match",
|
|
|
"points": 8,
|
|
|
"field": "",
|
|
|
"source": "IChO-2025",
|
|
|
"question": {
|
|
|
"context": "Draw the structures of compounds I, J, and K.",
|
|
|
"image": "images/1/1.6_ques.png",
|
|
|
"parsing_note": "The reaction diagram has been converted to reaction_scheme.",
|
|
|
"requirement": "Convert the drawn structures to SMILES format (stereochemistry not required).",
|
|
|
"reaction_scheme": [
|
|
|
{
|
|
|
"reactant_name": "H",
|
|
|
"reactant_smiles": "C[C@]1(C=C2)CCC[C@](CC(O)=O)(C1)C2=O",
|
|
|
"conditions": "1) H_{2}, Pd/C; 2) CH_{3}OH H^{+}",
|
|
|
"product_name": "I"
|
|
|
},
|
|
|
{
|
|
|
"reactant_name": "I",
|
|
|
"conditions": "1) HOCH_{2}CH_{2}OH, H^{+}; 2) NaOH, H_{2}O",
|
|
|
"product_name": "J"
|
|
|
},
|
|
|
{
|
|
|
"reactant_name": "J",
|
|
|
"conditions": "1) SOCl_{2}; 2) Et_{2}CuLi; 3) H^{+}, H_{2}O",
|
|
|
"product_name": "K"
|
|
|
},
|
|
|
{
|
|
|
"reactant_name": "K",
|
|
|
"conditions": "1) NaOH, H_{2}O, Δ",
|
|
|
"intermediate_smiles": "CC1=C2CC[C@]3(CCC[C@]2(CC1=O)C3)C",
|
|
|
"product_name": "Cv",
|
|
|
"product_smiles": "CC1([C@@]2(CC[C@]3(CCC[C@]2(C=C1)C3)C)[H])C"
|
|
|
}
|
|
|
]
|
|
|
},
|
|
|
"answer": [
|
|
|
{
|
|
|
"name": "I",
|
|
|
"image": "images/1/1.6_ans_I.png",
|
|
|
"smiles": "O=C1C=C[C@]2(CCC[C@]1(CC(OC)=O)C2)C",
|
|
|
"alternative_smiles": "O=C1C=CC2(CCCC1(CC(OC)=O)C2)C",
|
|
|
"points": 3,
|
|
|
"grading": {
|
|
|
"partial_credit": [
|
|
|
{
|
|
|
"condition": "if double bond is not reduced.",
|
|
|
"deduction": -2
|
|
|
},
|
|
|
{
|
|
|
"condition": "if ester is not formed",
|
|
|
"deduction": -1
|
|
|
}
|
|
|
],
|
|
|
"notes": "Stereochemistry will not be marked for I. Minimum score is 0 pt."
|
|
|
}
|
|
|
},
|
|
|
{
|
|
|
"name": "J",
|
|
|
"image": "images/1/1.6_ans_J.png",
|
|
|
"smiles": "CC1CC[C@@]([H])(C(C)(C)C2)[C@@]2([H])C(C)CCC1",
|
|
|
"alternative_smiles": "CC1CCC([H])(C(C)(C)C2)C2([H])C(C)CCC1",
|
|
|
"points": 2,
|
|
|
"grading": {
|
|
|
"partial_credit": [
|
|
|
{
|
|
|
"condition": "if acetal group is incorrect/not present.",
|
|
|
"deduction": -1
|
|
|
},
|
|
|
{
|
|
|
"condition": "if original ester is still present; protective group is in place.",
|
|
|
"deduction": -1
|
|
|
},
|
|
|
{
|
|
|
"condition": "if ester is formed with ethylene glycol.",
|
|
|
"deduction": -1.5
|
|
|
}
|
|
|
],
|
|
|
"notes": "Stereochemistry will not be marked for I. Minimum score is 0 pt."
|
|
|
}
|
|
|
},
|
|
|
{
|
|
|
"name": "K",
|
|
|
"image": "images/1/1.6_ans_K.png",
|
|
|
"smiles": "O=C1C=C[C@]2(CCC[C@]1(CC(CC)=O)C2)C",
|
|
|
"alternative_smiles": "O=C1C=CC2(CCCC1(CC(CC)=O)C2)C",
|
|
|
"points": 3,
|
|
|
"grading": {
|
|
|
"partial_credit": [
|
|
|
{
|
|
|
"condition": "If acetal protecting group is still present.",
|
|
|
"deduction": -1
|
|
|
},
|
|
|
{
|
|
|
"condition": "If acid is turned into acid chloride and protective group is removed.",
|
|
|
"deduction": -2
|
|
|
},
|
|
|
{
|
|
|
"condition": "If five-membered ring is already formed with an alcohol group still present.",
|
|
|
"deduction": -2
|
|
|
}
|
|
|
],
|
|
|
"notes": "Stereochemistry will not be marked for I. Minimum score is 0 pt."
|
|
|
}
|
|
|
}
|
|
|
]
|
|
|
},
|
|
|
{
|
|
|
"name": "IChO-2025_1.7-8",
|
|
|
"modality": "image + text",
|
|
|
"type": "Structure Construction",
|
|
|
"evaluation": "Structure Match",
|
|
|
"points": 4,
|
|
|
"field": "",
|
|
|
"source": "IChO-2025",
|
|
|
"question": {
|
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|
"context": "Humulene (Hu) is another sesquiterpene. It can be converted to α-caryophyllene alcohol (α-Ca), which is similar in structure to Cv. This conversion is an acid-catalysed hydration reaction which takes place via multiple intermediate structures. Incomplete structures of some intermediates, X and Y, are shown. The transformation from Hu to X is an acid-catalysed isomerisation reaction. Intermediate Y is charged.",
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"image": "images/1/1.7-8_ques.png",
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"parsing_note": "The reaction diagram has been converted to reaction_scheme.",
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"requirement": "Convert the completed structures to SMILES format.",
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"reaction_scheme": [
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{
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"reactant_name": "Hu",
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"reactant_smiles": "CC1(C)C/C=C(C)/CC/C=C(C)/C/C=C/1",
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"conditions": "H^{+} (cat.)",
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"product_name": "X",
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"product_smiles": "CC1CCC(C)(C)CCC(C)CCC1"
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},
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{
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"reactant_name": "X",
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"reactant_smiles": "CC1CCC(C)(C)CCC(C)CCC1",
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"conditions": "+H^{+}",
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"product_name": "Y",
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"product_smiles": "CC1(CC2C3(C)CCCC(C)C3C2C1)C"
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},
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{
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"reactant_name": "Y",
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"reactant_smiles": "CC1(CC2C3(C)CCCC(C)C3C2C1)C",
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"conditions": "1) H_{2}O, -H^{+}",
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"product_name": "α-Ca",
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"product_smiles": "CC1(C)CC(C2C1)C3(CCCC2(C3O)C)C"
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}
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]
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},
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"answer": [
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{
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"name": "X",
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"image": "images/1/1.7-8_ans_X.png",
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"smiles": "CC1=C\\CC/C(C)=C/CC(C)(C)C/C=C/1",
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"alternative_smiles": "C/C1=C/C=C/C(C)(C)C/C=C(C)/CCC1",
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"points": 2,
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"grading": {
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"partial_credit": [
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{
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"condition": "for each mistake down to zero.",
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"deduction": -1
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},
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{
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"condition": "if all double bonds are mirrored.",
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"deduction": -1
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}
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]
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}
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},
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{
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"name": "Y",
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"image": "images/1/1.7-8_ans_Y.png",
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"smiles": "CC1(C)CC2C3(CCC[C+](C3C2C1)C)C",
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"points": 2,
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"grading": {
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"partial_credit": [
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{
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"condition": "if any other charge or group has been added to the structure.",
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"deduction": -2
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}
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]
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}
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}
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]
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},
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{
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"name": "IChO-2025_1.9",
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"modality": "image + text",
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"type": "Qualitative Identification",
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"evaluation": "Selection Check",
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"points": 2,
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"field": "",
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"source": "IChO-2025",
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"question": {
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"context": "Five carbon atoms are circled in Hu. Through understanding the mechanism we can determine where these five carbon atoms end up in α-Ca. Circle the five corresponding carbon atoms in α-Ca which are circled in Hu.",
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"image": [
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{
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"Hu": "images/1/1.9_ques_Hu.png"
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},
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{
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"Y": "images/1/1.9_ques_α-Ca.png"
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}
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],
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"smiles": {
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"Hu": "CC1(C)CC/C=C(C)/CC/C=C(C)/C/C=C/1",
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"Y": "CC1(CC(C2(C)CCCC3(C)C2O)C3C1)C"
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},
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"parsing_note": "The structure in the image has been converted to SMILES format.",
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"requirement": "1) Count only carbon atoms (C) in the SMILES string from left to right, ignoring all other atoms like H, O, N. Number each carbon sequentially as C-1, C-2, C-3, etc. 2) In Hu, C-6, C-7, C-12, C-14, C-15 are circled based on Hu smiles. 2) Give the five corresponding carbon atoms in α-Ca which are circled in Hu, Output format: 'C-X, C-X'."
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},
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"answer": {
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"context": "C-5, C-6, C-8, C-12, C-13",
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"image": "images/1/1.9_ans.png",
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"grading": {
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"partial_credit": [
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{
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"condition": "if five circles are correct.",
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"deduction": 0
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},
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{
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"condition": "if four circles are correct and one incorrect or missing.",
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"deduction": -1
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},
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{
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"condition": "for more than five carbons circled or two or more incorrect/missing.",
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"deduction": -2
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}
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],
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"notes": "Minimum score is 0"
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},
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"points": 2
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}
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}
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]
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